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KCNQ2 binds CALM. 147 / 147
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"First, the structure alignment of KCNQ2-CaM apo and KCNQ2-CaM CBD shows that the CBD induces a 2–3 Å shift of VSD, which tends to disturb interactions of VSD and CaM (Fig.  xref )."
37857637
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"Since A-kinase-anchoring protein (AKAP) 79 XREF_BIBR, XREF_BIBR regulates CaM binding to KCNQ2 XREF_BIBR and serves as an adaptor protein for CaM and PKC XREF_BIBR, XREF_BIBR, the mechanism responsible for CaM mediated trafficking of KCNQ channels to the axonal surface may well converge with the ability of CaM to modulate PKC dependent inhibition of M-current via AKAP79/150 XREF_BIBR, XREF_BIBR and PIP 2 XREF_BIBR."
25077630
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"To reveal the HN37 activation mechanism, we determined two KCNQ2-CaM structures in the presence of both HN37 and PIP 2 , one with HN37 added to the protein sample first (KCNQ2-CaM HN37-PIP2(-) , Table  xref , Supplementary Fig.  xref ) and the other one with PIP 2 added first (KCNQ2-CaM PIP2-HN37 , Table  xref , Supplementary Fig.  xref )."
37857637
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"In the map of KCNQ2-CaM HN37-PIP2(-) , no PIP 2 molecule was assigned, and consequently, the KCNQ2-CaM HN37-PIP2(-) structure is in a closed state with two HN37 bound (Supplementary Fig.  xref ), similar to the KCNQ2-CaM HN37 structure (Fig.  xref )."
37857637
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"KCNQ2 subunit associates with another CaM binding protein as a constituent of the channel complex: AKAP79/150, a scaffold protein critical for KCNQ2 channel regulation xref , xref ."
24349250
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"In contrast, the KCNQ2-CaM PIP2-HN37 is in an open state with one HN37 (HN37 A ) and one PIP 2 bound (Fig.  xref )."
37857637
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"In KCNQ2-CaM PIP2-HN37 , PIP 2 binds in the cleft between VSD and PD and directly interacts with Lys327 in S6 (Fig.  xref ), similar to the observations in KCNQ2-CaM CBD-PIP2 (Fig.  xref ) ."
37857637
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"In combination, the experiments presented in Figure 3, Figure 4, Figure 5 suggest that impairing CaM binding to Kv7.2 reduces the number of functional channels at the plasma membrane, but the functional channels that did reach plasma membrane are likely to still bind CaM, as suggested previously (41)."
36549648
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"To analyze why HN37 B does not bind in the structure of KCNQ2-CaM PIP2-HN37 , we compare structures of KCNQ2-CaM PIP2-HN37 and KCNQ2-CaM HN37 (Fig.  xref )."
37857637
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"Calmodulin bound to the KCNQ2 subunit regulates channel trafficking and stabilizes channel activity."
24627475
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"Here we show that the L339R mutation in helix A, which is linked to human benign neonatal convulsions, perturbs CaM binding to KCNQ2 channels and prevents their correct trafficking to the plasma membrane."
19494108
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"The process appears to require at least two steps; the first involves the transient association of CaM with KCNQ2, and in the second, the complex adopts an "active" conformation that is more stable and is that which confers the capacity to exit the endoplasmic reticulum."
19494108
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"These data are entirely consistent with the concept that CaM bound to KCNQ2 acts as a Ca2+ sensor, conferring Ca2+ dependence to the trafficking of the channel to the plasma membrane and fully explaining the requirement of CaM binding for KCNQ2 function."
19494108
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"First, we introduced two mutations within the IQ domain of KCNQ3 : an isoleucine to alanine substitution at the position 342 (KCNQ3-I342A); and an alanine substitution of the residues 346 to 349 (KCNQ[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]"
24333508
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"Here we report cryo-electron microscopy (cryo-EM) structures of human KCNQ2-CaM in complex with three activators, namely the antiepileptic drug cannabidiol (CBD), the lipid phosphatidylinositol 4,5-bisphosphate (PIP 2 ), and HN37 (pynegabine), an antiepileptic drug in the clinical trial, in an either closed or open conformation."
37857637
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"Here authors report structures of KCNQ2-CaM in complex with cannabidiol, PIP2, and HN37 and elucidate the mechanisms of activation."
37857637
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"We present 2.5–3.5 Å resolution structures of human KCNQ2-CaM complex in the CBD-bound closed, HN37-bound closed, and CBD-PIP 2 -bound open states (Table  xref )."
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"In addition, Ca 2 + / CaM binds the 1-5-10 motifs of both KCNQ2 and KCNQ3 with a low-affinity, and favours subunit interaction."
24333508
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"Structure determination of KCNQ2-CaM in the presence of PIP 2 ."
37857637
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"Previously, we determined the apo KCNQ2-CaM structure (KCNQ2-CaM apo , PDB: 7CR3) xref , which was in decoupled conformation with activated VSDs and a closed gate."
37857637
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"Because PIP 2 can potentiate the activation of KCNQ channels by enhancing the E–M coupling, to capture an open-state KCNQ2, we solved the structure of the KCNQ2-CaM complex in the presence of 1 mM PIP 2 (KCNQ2-CaM PIP2(-) , where (-) indicates that PIP 2 was added in the protein sample but not observed in the structure throughout this paper) at 2.7 Å resolution (Supplementary Fig.  xref , Table  xref )."
37857637
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"The KCNQ2-CaM PIP2(-) structure is similar to the KCNQ2-CaM apo structure, with activated VSDs and a closed gate xref ."
37857637
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"To reveal the molecular mechanism of CBD activation on KCNQ2-CaM, we next determined the CBD-bound KCNQ2-CaM structure (KCNQ2-CaM CBD ) at 3.3 Å resolution (Fig.  xref , Table  xref , Supplementary Figs.  xref – xref , xref )."
37857637
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"In the TMD, the high-quality map of KCNQ2-CaM CBD allows us to clearly resolve two CBD molecules located in the hydrophobic cleft formed by S6 from the first subunit (S6 I ), S5, pore helix (PH), and S6 from the second subunit (S5 II , PH II , and S6 II ), and S1 from the third subunit (S1 III ) (Fig.  xref )."
37857637
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"Structural comparison of KCNQ2-CaM CBD and KCNQ2-CaM apo reveals that the two CBDs induce a rotamer change of Trp236 in S5 II , which eliminates the potential clash with CBD A on one hand and facilitates the formation of a hydrogen bond with CBD B on the other hand (Fig.  xref )."
37857637
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"The gate in KCNQ2-CaM CBD remains closed in the absence of PIP 2 (Fig.  xref ), hindering the elucidation of the activation mechanism of CBD."
37857637
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"The CBD- and PIP 2 -bound open-state structure of KCNQ2-CaM."
37857637
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"To decipher the CBD and PIP 2 activation mechanism, we then determined the PIP 2 -CBD-bound KCNQ2-CaM structure (KCNQ2-CaM CBD-PIP2 ) at 3.1 Å resolution (Fig.  xref , Table  xref , Supplementary Figs.  xref – xref xref )."
37857637
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"Like those in KCNQ2-CaM CBD , two CBD molecules are clearly observed in the map of KCNQ2-CaM CBD-PIP2 (Fig.  xref )."
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"The second group found that both wt CaM and DN CaM interact with KCNQ2, consistent with our results that DN CaM can act as a dominant negative in CaM actions."
12810850
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"HB which sits on the right side of HA in KCNQ2-CaM apo moves to the left side of HA in KCNQ2-CaM CBD-PIP2 (Fig.  xref )."
37857637
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"Given the importance that both groups ascribed to both of these regions for CaM binding to KCNQ2 subunits, we were surprised to find in the current work that IQ 2, but not IQ 1, produced a Ca 2+ -dependent gel shift of CaM."
12810850
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"Therefore, bound with both CBD and PIP 2 , KCNQ2-CaM CBD-PIP2 is in an open state."
37857637
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"This KCNQ2-CaM CBD-PIP2 structure resembles the previously reported PIP 2 -bound open-state structures of KCNQ1 and KCNQ4 xref , xref , xref ."
37857637
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"Second, structure alignment KCNQ2-CaM CBD and KCNQ2-CaM CBD-PIP2 shows that PIP 2 induces a further 3–4 Å shift of VSD (Fig.  xref ), which completely destroys interactions of VSD and CaM, resulting in the release of CaM and HA/HB from the VSD, followed by the rotation of CaM and HA/HB, as well as the folding of S6 and HA into one continuous helix (Fig.  xref )."
37857637
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"These CBD and PIP 2 activation insights are obtained from comparisons of the KCNQ2-CaM structures with or without ligands."
37857637
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"The first CaM-binding motif has a sequence that conforms partially to the consensus IQ motif, but both wild-type CaM and a Ca2+-insensitive CaM mutant bind to KCNQ2."
12223552
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"Here we show that the L339R mutation in helix A, which is linked to human benign neonatal convulsions, perturbs CaM binding to KCNQ2 channels and prevents their correct trafficking to the plasma membrane."
19494108
sparser
"However, in vitro the binding of PIP 2 in the activated VSD is not that strong and PIP 2 is easy to dissociate, which can explain why we were unable to capture the PIP 2 -bound open-state KCNQ2-CaM structure in the presence of PIP 2 alone (KCNQ2-CaM PIP2(-) ) (Fig.  xref )."
37857637
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"CK2-mediated phosphorylation of CaM regulates the M-current by facilitating CaM binding to KCNQ2 [19] ."
25109776
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"Interestingly, two different KCNQ2-CaM F104A maps were reconstructed from one dataset, which were designated KCNQ2-CaM F104A-CBD-PIP2(-)-I and KCNQ2-CaM F104A-CBD-PIP2-II at 2.7 Å and 3.5 Å resolutions, respectively (Fig.  xref , Table  xref , Supplementary Figs.  xref – xref , xref )."
37857637
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"Interestingly, KCNQ2-CaM F104A-CBD-PIP2(-)-I remains in a closed state with no PIP 2 bound while KCNQ2-CaM F104A-CBD-PIP2-II is in an open state with the PIP 2 bound (Fig.  xref )."
37857637
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"The number ratio of particles used for the final reconstruction of KCNQ2-CaM F104A-CBD-PIP2(-)-I and KCNQ2-CaM F104A-CBD-PIP2-II is ~4: 1 (Fig.  xref )."
37857637
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"In comparison, only the open-state 3D reconstruction KCNQ2-CaM PIP2-CBD was obtained from the WT sample with both PIP 2 and CBD bound."
37857637
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"The differential distribution of the KCNQ2-CaM F104A-CBD-PIP2 particles with only CBD A bound in closed and open states indicates that with the presence of PIP 2 , (i) CBD A alone is able to stabilize some KCNQ2 channels in the open conformation, which accounts for ~20% of total channels, and (ii) CBD B further enhances this stabilization and dramatically increases the ratio of the open-conformation channels."
37857637
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"These data are entirely consistent with the concept that CaM bound to KCNQ2 acts as a Ca2+ sensor, conferring Ca2+ dependence to the trafficking of the channel to the plasma membrane and fully explaining the requirement of CaM binding for KCNQ2 function."
19494108
sparser
"To reveal the activation mechanism of HN37 on KCNQ2, we then determined the HN37-bound KCNQ2 structure (KCNQ2-CaM HN37 ) at 2.5 Å resolution (Fig.  xref , Table  xref , Supplementary Fig.  xref )."
37857637
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"CaM was able to bind KCNQ2(C527R) protein in the calcium (–) condition ( xref )."
24349250
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"In KCNQ2-CaM HN37 , to our surprise, there are also two HN37 molecules bound in each KCNQ2 subunit (Fig.  xref )."
37857637
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"KCNQ2-CaM HN37 is also in decoupled conformation, with activated VSDs and a closed gate (Fig.  xref )."
37857637
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"However, in contrast to the wild-type KCNQ2 subunit, addition of 100 µM calcium further increased binding of CaM to KCNQ2(C527R) ( xref )."
24349250
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"5 Å resolution structures of human KCNQ2-CaM complex in the CBD-bound closed, HN37-bound closed, and CBD-PIP -bound open states (Table 1)."
37857637
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"Because PIP can potentiate the activation of KCNQ channels by enhancing the E–M coupling, to capture an open-state KCNQ2, we solved the structure of the KCNQ2-CaM complex in the presence of 1 mM PIP (KCNQ2-CaM , where (-) indicates that PIP was added in the protein sample but not observed in the structure throughout this paper) at 2."
37857637
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"Of note, the signal of CaM 3 pulled down with Kv7.4 channels was stronger than WT CaM in the presence of 2 mM CaCl 2 , matching the observation by xref , who reported that longer exposure to calcium decreased CaM binding to Kv7.2 channels."
33551832
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"With the presence of PIP 2 in KCNQ2-CaM PIP2-HN37 , HN37 B was unable to bind."
37857637
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"However, we could not rule out the possibility that the two-HN37-bound KCNQ structures (KCNQ2-CaM HN37 and KCNQ2-CaM HN37-PIP2(-) ) may present an in vivo transient state after which HN37 B will be replaced by PIP 2 easily."
37857637
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"We first align structures of KCNQ2-CaM HN37 and KCNQ2-CaM CBD , which shows that HN37 B clashes with CBD A and Trp236 side chain, but not CBD B . Thus, this HN37 B is unlikely to co-bind with two CBDs (Supplementary Fig.  xref )."
37857637
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"Moreover, binding of WT CaM to KCNQ2 can moderately reduce the constitutive current through KCNQ2 homomeric channels by changing channel structure."
23630338
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"CK2-mediated phosphorylation of CaM regulates the M-current by facilitating CaM binding to KCNQ2 [19] ."
25109776
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"KCNQ2 and CaM complex were heterologously expressed in Human Embryonic Kidney (HEK) 293S suspension cells (Life Technologies, ATCC, #CRL-3022) maintained at 30 °C in SMM 293-TI complete medium (Sino Biological Inc.) supplemented with 2% fetal bovine serum (FBS, Yeasen Biotechnology (Shanghai) Co., Ltd.)."
37857637
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"These results support the hypothesis that changes in calcium levels alter KCNQ2-CaM binding, which leads to the suppression of the current."
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"The following two rounds of 3D classification with 940,410 selected particles were performed using the map of human KCNQ2-CaM complex (PDB: 7CR3) as a reference."
37857637
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"Here the CBD- and PIP 2 -bound open-state structure of KCNQ2-CaM reveals a different binding site and a different role of PIP 2 ."
37857637
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"The amino acid assignment was achieved based on the clearly defined density for bulky residues (Phe, Trp, Tyr, and Arg) and the model of KCNQ2-CaM complex (PDB: 7CR3) was used as a reference."
37857637
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"These results suggest that a change in the configuration of CaM–KCNQ2 binding induced by elevated intracellular calcium led to the reduction in PIP2 affinity of the KCNQ2 channel."
24349250
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"The current study suggests that not only the calcium-induced dissociation of CaM, but also a change in the configuration of CaM-KCNQ2 binding could suppress the KCNQ2 current."
24349250
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"We also demonstrated that a CaM deficient mutant channel, KCNQ2(R353G), showed augmented ionomycin-induced current suppression, which suggests that a change in the KCNQ2-CaM interaction is critical for the suppression."
24349250
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"This review aims to summarize the functional findings together with the different mechanisms of action proposed for the interaction of CaM with Kv7.2 channels."
30022004
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"Since the KCNQ2(R353G) channel with impaired CaM binding and low PIP2 affinity xref showed a stronger response to ionomycin, it would be reasonable to assume that the KCNQ2-CaM interaction regulates PIP2 affinity of the KCNQ2 subunit as we reported previously xref ."
24349250
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"To probe for CaM interactions with KCNQ2–5, we performed immunoprecipitation (IP) experiments, followed by immunoblotting."
12810850
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"It has been proposed that Ca 2+ does not influence the association of CaM with Kv7.2/7.3 heteromers [ xref ], or that the interaction of Kv7.2 with CaM is weaker [ xref ] or stronger in the absence of Ca 2+ [ xref , xref , xref , xref , xref , xref ]."
30022004
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"The second group found that both wt CaM and DN CaM interact with KCNQ2, consistent with our results that DN CaM can act as a dominant negative in CaM actions."
12810850
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"Given the importance that both groups ascribed to both of these regions for CaM binding to KCNQ2 subunits, we were surprised to find in the current work that IQ 2 , but not IQ 1 , produced a Ca 2+ -dependent gel shift of CaM."
12810850
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"Furthermore, in vitro assays have demonstrated that apoCaM or Ca 2+ -CaM can bind peptides containing the sequences of Kv7.2 hA or hB [ xref , xref , xref , xref , xref , xref ]."
30022004
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"Calmodulin bound to the KCNQ2 subunit regulates channel trafficking and stabilizes channel activity."
24627475
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"Using immunocytochemistry and the cluster of differentiation 4 (CD4) membrane protein as a trafficking reporter, we demonstrate that fusion of KCNQ2 carboxy-terminal tail is sufficient to target CD4 protein to the axonal surface whereas inhibition of calmodulin binding to KCNQ2 abolishes axonal surface expression of CD4 fusion proteins by retaining them in the endoplasmic reticulum."
25077630
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"In summary, it appears that the strength of the interaction of CaM with Kv7.2 channels is altered by Ca 2+ occupancy."
30022004
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"Disruption of calmodulin binding to KCNQ2 also impairs enrichment of heteromeric KCNQ2 and KCNQ3 channels at the axonal surface by blocking their trafficking from the endoplasmic reticulum to the axon."
25077630
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"Since CaM interaction with KCNQ2 is required for functional expression of KCNQ channels in non neuronal cells XREF_BIBR, XREF_BIBR, XREF_BIBR, we hypothesized that CaM regulates preferential targeting of KCNQ channels to the axonal surface."
25077630
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"To test whether CaM interaction with KCNQ2 regulates the targeting of CD4-Q2C to the axonal surface, we introduced point mutations in helix A of KCNQ2 including two BFNC mutations, L339R and R353G XREF_BIBR (XREF_FIG)."
25077630
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"In contrast, the A343D mutation, which blocked CaM binding to KCNQ2 (XREF_FIG) XREF_BIBR, XREF_BIBR, abolished surface and intracellular expression of HA-KCNQ3 and KCNQ2 channels at the AIS and distal axons (XREF_FIG, XREF_FIG) and reduced the surface " Axon and Dendrite " ratio to below 1 (XREF_FIG)."
25077630
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"Despite a modest reduction of CaM binding to KCNQ2 by the R353G mutation (XREF_FIG) XREF_BIBR, XREF_BIBR, the R353G mutant channels were localized to the AIS and axonal surface to a similar extent as the wild-type channels (XREF_FIG)."
25077630
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"Disruption of CaM binding to KCNQ2 impairs trafficking of HA-KCNQ3 and KCNQ2 channels from the ER to the axon."
25077630
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"According to XREF_BIBR, calmodulin binding to KCNQ2 channels stabilized PI (4,5) P 2 channel binding."
24470487
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"The R353G mutation located distal to the IQ motif (XREF_FIG) has been shown to moderately reduce CaM binding to KCNQ2 in HEK293T cells XREF_BIBR, XREF_BIBR."
25077630
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"These results together suggest that disruption of CaM binding to KCNQ2 impairs the trafficking of CD4-Q2C proteins from the ER to the AIS and distal axons."
25077630
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"Disruption of CaM binding to KCNQ2 inhibits enrichment of HA-KCNQ3 and KCNQ2 channels at the axonal surface."
25077630
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"To test whether CaM binding to KCNQ2 promotes trafficking of HA-KCNQ3 and KCNQ2 channels from the ER to the axon, we performed pulse-chase experiments after removal of BFA."
25077630
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"These results together indicate that disruption of CaM interaction with KCNQ2 by the A343D mutation impairs the trafficking of HA-KCNQ3 and KCNQ2 channels from the ER to the axon."
25077630
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"Although CaM can still interact with KCNQ3 subunits XREF_BIBR, XREF_BIBR, the A343D mutation, which abolished CaM binding to KCNQ2 (XREF_FIG), prevented surface and intracellular expression of intact HA-KCNQ3 and KCNQ2 channels at the AIS and distal axons (XREF_FIG - XREF_FIG), consistent with a recent study reporting altered neuronal distribution of heteromeric channels by the I340A mutation XREF_BIBR."
25077630
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"In contrast, the BFNC R353G mutation located distal to the IQ motif modestly reduced but did not abolish CaM binding to KCNQ2 (XREF_FIG) and had minimal effect on the polarized axonal surface expression of HA-KCNQ3 and KCNQ2 channels (XREF_FIG)."
25077630
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"According to xref , calmodulin binding to KCNQ2 channels stabilized PI(4,5)P 2 channel binding."
24470487
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"Since the R353G mutation in KCNQ2 reduces CaM binding to heteromeric KCNQ2 and KCNQ3 channels only by 20% XREF_BIBR, XREF_BIBR, our results suggest that a greater degree of impairment in CaM binding to KCNQ2 is needed to prevent targeting of heteromeric channels to the axonal surface."
25077630
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"In this study, we investigated the molecular mechanism of KCNQ2 current suppression mediated by calcium bound calmodulin."
24349250
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"Identification of a binding pocket for ML277 on KCNQ1 allowed comparison with the recently described binding of ML213 and retigabine to KCNQ4-CaM and KCNQ2-CaM xref , xref ."
35768468
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"Our docking analyses indicated that residues in KCNQ2-CaM and KCNQ4-CaM greatly reduced the binding ability of ML277 to these subfamily members."
35768468
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"Previously, we reported that the de novo dominant EE mutation M546V in human Kv7.2 blocks calmodulin binding to Kv7.2 and axonal surface expression of Kv7 channels via their intracellular retention."
35444503
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"The first CaM binding motif has a sequence that conforms partially to the consensus IQ motif, but both wild-type CaM and a Ca2 +-insensitive CaM mutant bind to KCNQ2."
12223552
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"Mutations in the Kv7.2 CaM binding domain interfere with the PIP activation of the channel [57], suggesting that CaM might compete with PIP [58]."
30022004
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"In the present study, we show that the IQ motif of KCNQ3 regulates the formation of a stable CaM/KCNQ2/3 complex and the traffic of KCNQ2/3 channels at the AIS."
24333508
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"Using immunocytochemistry and the cluster of differentiation 4 (CD4) membrane protein as a trafficking reporter, we demonstrate that fusion of KCNQ2 carboxy-terminal tail is sufficient to target CD4 protein to the axonal surface whereas inhibition of calmodulin binding to KCNQ2 abolishes axonal surface expression of CD4 fusion proteins by retaining them in the endoplasmic reticulum."
25077630
sparser
"Disruption of calmodulin binding to KCNQ2 also impairs enrichment of heteromeric KCNQ2/KCNQ3 channels at the axonal surface by blocking their trafficking from the endoplasmic reticulum to the axon."
25077630
sparser
"Since CaM interaction with KCNQ2 is required for functional expression of KCNQ channels in non-neuronal cells xref , xref , xref , we hypothesized that CaM regulates preferential targeting of KCNQ channels to the axonal surface."
25077630
sparser
"To test whether CaM interaction with KCNQ2 regulates the targeting of CD4-Q2C to the axonal surface, we introduced point mutations in helix A of KCNQ2 including two BFNC mutations, L339R and R353G xref ( xref )."
25077630
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"Considering the modest effect of CaM1234 on the axonal surface expression of HA-KCNQ3 and KCNQ2 channels (XREF_FIG), CaM bound to KCNQ2 may act as a Ca 2+ sensor for modulating not only the M-current, but also the channel density at the axonal membrane."
25077630
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"Two recent studies have determined the structures of Kv7.2-CaM complexes."
30022004
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"For instance, calmodulin binding to the C-terminal A and B helices of KCNQ2 leads to ER retention, limit the rate of KCNQ2 exit from ER, and reducing the number of channels that reach the plasma membr[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]"
31778691
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"The structural elements critical for CaM binding to KCNQ2 lie in two conserved motifs in the proximal half of the channel C-terminal domain."
12223552
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"The R353G mutation located distal to the IQ motif ( xref ) has been shown to moderately reduce CaM binding to KCNQ2 in HEK293T cells xref , xref ."
25077630
sparser
"These results together suggest that disruption of CaM binding to KCNQ2 impairs the trafficking of CD4-Q2C proteins from the ER to the AIS and distal axons."
25077630
sparser
"Disruption of CaM binding to KCNQ2 inhibits enrichment of HA-KCNQ3/KCNQ2 channels at the axonal surface."
25077630
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"Despite a modest reduction of CaM binding to KCNQ2 by the R353G mutation ( xref ) xref , xref , the R353G mutant channels were localized to the AIS and axonal surface to a similar extent as the wild-type channels ( xref )."
25077630
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"Disruption of CaM binding to KCNQ2 impairs trafficking of HA-KCNQ3/KCNQ2 channels from the ER to the axon."
25077630
sparser
"To test whether CaM binding to KCNQ2 promotes trafficking of HA-KCNQ3/KCNQ2 channels from the ER to the axon, we performed pulse-chase experiments after removal of BFA."
25077630
sparser
"These results together indicate that disruption of CaM interaction with KCNQ2 by the A343D mutation impairs the trafficking of HA-KCNQ3/KCNQ2 channels from the ER to the axon."
25077630
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"The interaction of the Kv7.2 C-terminus with CaM was used as positive control."
17482572
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"Although CaM can still interact with KCNQ3 subunits xref , xref , the A343D mutation, which abolished CaM binding to KCNQ2 ( xref ), prevented surface and intracellular expression of intact HA-KCNQ3/KCNQ2 channels at the AIS and distal axons ( xref – xref ), consistent with a recent study reporting altered neuronal distribution of heteromeric channels by the I340A mutation xref ."
25077630
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"In contrast, the BFNC R353G mutation located distal to the IQ motif modestly reduced but did not abolish CaM binding to KCNQ2 ( xref ) and had minimal effect on the polarized axonal surface expression of HA-KCNQ3/KCNQ2 channels ( xref )."
25077630
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"As suggested by secondary structure prediction, the mutation residue is likely to disrupt the amphipatic a-helical structure in helix B, which appears to be necessary for proper interaction of CaM wit[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]"
17482572
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"Since the R353G mutation in KCNQ2 reduces CaM binding to heteromeric KCNQ2/KCNQ3 channels only by 20% xref , xref , our results suggest that a greater degree of impairment in CaM binding to KCNQ2 is needed to prevent targeting of heteromeric channels to the axonal surface."
25077630
sparser
"Considering the modest effect of CaM1234 on the axonal surface expression of HA-KCNQ3/KCNQ2 channels ( xref ), CaM bound to KCNQ2 may act as a Ca 2+ sensor for modulating not only the M-current, but also the channel density at the axonal membrane."
25077630
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"In addition, we demonstrate that mutations that interfere with CaM binding to Kv7.2 and Kv7.3 reduced channel membrane abundance and activity, but these mutants retained zinc sensitivity."
36549648
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"In the apo state of KCNQ2-CaM (HsKCNQ2-CaM apo , Table 1 ), VSD is in an activated state while the activation gate remains closed, indicating a decoupled conformation."
37976835
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"To probe the activation mechanism of the antiepileptic drug retigabine, we determined the RTG-bound human KCNQ2-CaM structure (HsKCNQ2-CaM RTG , Table 1 ) and identified the RTG binding site in PD."
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"Both WT and dominant-negative CaM bind to the C terminus of KCNQ2 ( xref ) and (a) mutations in KCNQ2 that affect CaM binding, (b) expression of dominant-negative CaM, or (c) expression of a “CaM sponge” lead to retention of KCNQ2 homomeric channels in the ER ( xref ; xref ; xref )."
23630338
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"Moreover, binding of WT CaM to KCNQ2 can moderately reduce the constitutive current through KCNQ2 homomeric channels by changing channel structure ( xref )."
23630338
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"CK2 phosphorylated SK2 bound CaM but not KCNQ2 bound CaM, thereby selectively regulating Ca 2+ gating of SK2 channels."
18701069
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"We also solved the ztz240-bound human KCNQ2-CaM structure (HsKCNQ2-CaM ztz240 , Table 1 ), which clearly shows that ztz240 binds in the side cleft between S3 and S4 in VSD, a new ligand binding site i[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]"
37976835
sparser
"Although we captured different conformations of KCNQ2-CaM with ligands, both RTG-bound and ztz240-bound KCNQ2-CaM are basically in the same closed state [ 62 ]."
37976835
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"Reducing CaM binding to Kv7.2 does not compromise zinc-induced potentiation."
36549648
reach
"After the KCNQ2 and CaM complex was purified by immunoprecipitation in calcium (-) condition, dissociation of CaM from KCNQ2 protein was examined by exposing KCNQ2-CaM resin to calcium (XREF_FIG)."
24349250
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"It was shown previously that I340E substitution in helix A or S511D substitution in helix B (Fig. 3A) reduce CaM binding to Kv7.2 and also reduce plasma membrane expression of the channels as well as the whole cell currents generated (41, 42)."
36549648
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"We also confirmed the effect of the mutations on Kv7.2–CaM interaction ( xref B )."
36549648
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"In combination, the experiments presented in xref , xref , xref suggest that impairing CaM binding to Kv7.2 reduces the number of functional channels at the plasma membrane, but the functional channels that did reach plasma membrane are likely to still bind CaM, as suggested previously ( xref )."
36549648
sparser
"CK2 phosphorylated SK2-bound CaM but not KCNQ2-bound CaM, thereby selectively regulating Ca 2+ gating of SK2 channels."
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"(iii) Consistent with the previous literature (41, 42), mutations that interfere with CaM binding to Kv7.2 and Kv7.3 reduce channel membrane abundance and activity, but these mutants retain sensitivity to zinc."
36549648
sparser
"In KCNQ4-CaM, both RTG and ML213 bind in the same pocket to the RTG binding pocket in KCNQ2-CaM [ 62–64 ], suggesting the conservation of the ligand binding mode in neuronal KCNQ channels."
37976835
sparser
"Reducing CaM binding to Kv7.2 does not compromise zinc-induced potentiation."
36549648
sparser
"It was shown previously that I340E substitution in helix A or S511D substitution in helix B ( xref A ) reduce CaM binding to Kv7.2 and also reduce plasma membrane expression of the channels as well as the whole cell currents generated ( xref , xref )."
36549648
sparser
"Our prediction thus supports these results by highlighting the importance of the interactions between KCNQ2 and the CaM proteins."
27307626
sparser
"In KCNQ2-CaM RTG , RTG binds in a hydrophobic pocket of VGICs lined by S5, pore helix, S6, and the S6 from the adjacent subunit."
37976835
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"Here, we have studied this functional interaction using fluorescence and NMR spectroscopy, in order to compare the association between Kv7.2 and full-length CaM 1-148 with that between Kv7.2 and the isolated N- (CaM 1-78) and C-domain (CaM 79-148) fragments XREF_BIBR."
24489773
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"Although the binding of CaM with Kv7.2 is not fully recapitulated by its individual segments XREF_BIBR, this analysis helps in understanding how CaM interacts with the channel."
24489773
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"Recent studies have shown that calmodulin (CaM) binds to the KCNQ2 and KCNQ3 C termini and may function as an auxiliary channel subunit XREF_BIBR, XREF_BIBR, XREF_BIBR."
19675672
sparser
"The Interaction between KCNQ2 Channels and Calmodulin is Regulated by CK2-Mediated Phosphorylation of the Lobe Linker."
32075037
sparser
"Calmodulin (CaM) binds to two intracellular C-terminal segments of Kv7.2 channels, helices A and B, and it is required for exit from the endoplasmic reticulum."
24489773
sparser
"CaM binds simultaneously to two sites of Kv7.2 in a 1∶1 stoichiometry xref ; xref ."
24489773