IndraLab
Statements
sparser
"Phosphorylated eIF3F seems to facilitate the formation of immature-nonfunctional eIF3 complex since the phosphorylated eIF3F does not exist in free form at both interphase and M phase as shown in the fraction D of Fig. S6. (2) Phosphorylated eIF3F may make a complex with an unknown protein, which in turn induces translational repression during M phase."
sparser
"After anti-Fas or staurosporine treatments in human melanoma cells, the caspase-processed C-terminal fragment CDK11p46 strongly interacts with eIF3f via its Mov34 domain [ xref ] and, due to its kinase activity, phosphorylates eIF3f inducing the inhibition of translation (Fig. xref )."
sparser
"Considering these phenomena, we speculate three plausible mechanisms of translational repression by phosphorylated eIF3F. (1) Phosphorylated eIF3F may compose an immature-nonfunctional eIF3 complex lacking some of eIF3 subunits, which blocks completion of eIF3 complex formation."
sparser
"We further investigated the effects of eIF3F phosphorylation by CDK11/p58 on M phase translation using newly established HeLa cell lines ectopically expressing either wild-type eIF3F [eIF3F(WT)] or unphosphorylatable eIF3F mutants [eIF3F(A1A2) and eIF3F(A3A4)] (Figs. xref , xref )."
sparser
"The result indicates that CDK11/p58 is responsible for the M phase-specific phosphorylation of eIF3F. However, we cannot completely rule out the possibility of indirect phosphorylation of eIF3F by CDK11/p58 via an unidentified kinase activated by CDK11/p58 even though the indirect phosphorylation of eIF3F is less likely since CDK11/p58 associates with eIF3F (Fig. xref )."
sparser
"This work also showed that p70S6K1 interacts with, and phosphorylates eIF3f, leading the authors to suggest that p70S6K1 phosphorylates eIF3 to stimulate the Paip1-eIF3 interaction and promotes translation initiation. xref Whether mTOR or p70S6K directly phosphorylates eIF3f in C2C12 cells or the effects of ablation of eIF3f on differentiation are unknown at this time."
sparser
"The results suggest that the hyper-phosphorylation of eIF3F in M phase is solely attributed to CDK11/p58 and that the basal phosphorylation of eIF3F, which remains at the same level across the cell cycle in CDK11 knockdown cells (Fig. xref b), is likely executed by an unknown kinase(s) other than CDK11."
sparser
"Since eIF3f serves as a connecting platform between mTOR-raptor and S6K1 in
muscle cells ( xref ) and
mutation of the C-terminal lysines in eIF3f increases phosphorylation of S6K1,
we assessed the binding affinities of both eIF3f wt and mutant eIF3f
K 5–10 R proteins with S6K1 and mTOR-raptor."
sparser
"Considering these data and our results presented here, which shows that CDK11/p58 actively reduces cap-dependent translation by phosphorylating eIF3F, the effect of CDK11/p58 expression in 14-3-3σ knockdown cells is, at least in part, attributed to cap-dependent translational repression by CDK11/p58."
sparser
"Blocking eIF3F phosphorylation by knockdown of CDK11/p58 (Fig. xref c) or by overproduction of unphosphorylatable eIF3F (Fig. xref ) in M phase cells, synchronized by nocodazole treatment, restored translation in M phase by approximately 35% and 50%, respectively, compared with translation in interphase (Figs. xref , xref )."
sparser
"To investigate whether the specific eIF3f phosphorylation by CDK11 p46 alters the association between eIF3f and eIF3 core complex, we performed co-immunoprecipitation with specific antibodies against the eIF3b and eIF3f in eIF3f, eIF3f SATA or eIF3f SETE (phosphorylation mimic mutant) transfected cells."
sparser
"Since CDK11/p58 is specifically expressed during mitosis (Fig. xref b) and interacts with eIF3F (Fig. xref ), we investigated whether CDK11/p58 is responsible for the M phase-specific phosphorylation of eIF3F. Knockdown of CDK11 drastically reduced the level of phosphorylated eIF3F in M phase cells to that in interphase cells (Fig. xref b, compare lane 4 with 2 and 3)."