PSTPIP is a substrate of XXXX and serves as a scaffold guiding @entity70724 toward a specific dephosphorylation of @entity70725 .

@entity29687 @entity19640 @entity17225 @entity70725 @entity669 @entity70724
PSTPIP is a @entity669 -phosphorylated protein involved in the organization of the cytoskeleton. Its ectopic expression induces filipodial-like membrane extensions in NIH 3T3 cells. We previously observed a defect in cytokinesis and an increase in the @entity669 phosphorylation of PSTPIP in @entity70724 -deficient fibroblasts. In this article, we demonstrate that @entity70724 and PSTPIP are found in the same complexes in vivo and that they interact directly through the CTH domain of @entity70724 and the coiled-coil domain of PSTPIP. We tested pathways that could regulate the @entity669 phosphorylation of PSTPIP. We found that the activation of the epidermal growth factor and platelet-derived growth factor receptors can induce PSTPIP phosphorylation. With the use of the @entity29687 inhibitor, we demonstrate that @entity19640 kinases are not involved in the epidermal growth factor-mediated phosphorylation of PSTPIP. Together with previous results, this suggests that @entity17225 is the critical @entity669 kinase downstream of growth factor receptors responsible for PSTPIP phosphorylation. We also demonstrate that @entity70724 dephosphorylates PSTPIP at @entity669 344. Importantly, we identified @entity669 344 as the main phosphorylation site of PSTPIP by performing tryptic phosphopeptide maps. This is an important finding since @entity669 367 of PSTPIP was also proposed as a candidate phosphorylation site involved in the negative regulation of the association between PSTPIP and @entity70725 . In this respect, we observed that the PSTPIP. @entity70725 complex is stable in vivo and is not affected by the phosphorylation of PSTPIP. Furthermore, we demonstrate that PSTPIP serves as a scaffold protein between @entity70724 and @entity70725 and allows @entity70724 to dephosphorylate @entity70725 . This finding suggests a possible mechanism for @entity70724 to directly modulate actin remodeling through the PSTPIP- @entity70725 interaction.
