IndraLab

"Interestingly, SAP97 also interacts with the 3 last residues of Kv4.2/4.3 (Ser-Ala-Leu) and Kv1.5 (Thr-Asp-Val) to potentially target and/or anchor ion channels to cell surface [ xref – xref ]."

"But even if SAP97 does bind the Kv1.5 C-terminus under specific conditions, that fact cannot explain the lack of dependence of the SAP97-mediated current enhancement on the extreme Kv1.5 C-terminus."

No evidence text available

"SAP97 appeared to be largely distributed along Z-lines In order to further test whether or not Kv1.5 and SAP97 directly interact in atrial and/or ventricular myocytes, we conducted co-immunoprecipitat[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]"

"This is unlikely to be due to detergent disruption of the Kv1.5–SAP97 interaction."

"It remains formally possible that Kv1.5 and SAP97 do directly interact but that the interaction is fleeting."

No evidence text available

"For this reason, we examined the interaction between Kv1.5 and SAP97, a PDZ protein that is widely expressed in mammalian heart [20] ."

No evidence text available

"Indeed, given this stark difference in effects of SAP97 on most Kv1 channels versus its effect on Kv1.5, it would be surprising if SAP97 did in fact bind Kv1.5."

"SAP97 and Kv1.5 subunits can interact, directly or indirectly, both in the heart and in heterologous systems. xref , xref Adenoviral overexpression of SAP97 in neonatal rat atrial myocytes leads to clustering of endogenous Kv1.5 subunits at myocyte-myocyte contacts and an increase in both I Kur and the number of 4-aminopyridine-sensitive potassium channels in cell-attached membrane patches. xref On the other hand, pull-down and coimmunoprecipitation assays in cardiac myocytes showed that the Kv4 channel C terminus, SAP97, and CaMKII interact together, and that the interaction is suppressed by SAP97 silencing and enhanced by SAP97 overexpression. xref In HEK293 cells, SAP97 silencing reproduced the effects of CaMKII inhibition on current kinetics and suppressed Kv4/CaMKII interactions."

No evidence text available

"The results presented here exclude a role of SAP97 binding to Kv1.5 in effecting the current enhancement and show that a specific N-terminal threonine residue (T15) is required in this phenomenon."

"The results of all of the experiments described above are inconsistent with a typical PDZ–extreme C-terminal interaction between SAP97 and Kv1.5."

"Perhaps in COS-7 cells the state of the channel is permissive of a stable SAP97-Kv1.5 interaction that is not seen in other cell types (including heart)."