Role of FRNK tyrosine phosphorylation in vascular smooth muscle spreading and migration

Koshman, Yevgeniya E.; Engman, Steven J.; Kim, Tae-Hoon; Iyengar, Rekha; Henderson, Kyle K.; Samarel, Allen M.

doi:10.1093/cvr/cvp322

Cited by 21 publications

(25 citation statements)

References 34 publications

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“…As is evident from Figure 4, wtFRNK markedly inhibited cell migration, confirming previous results. 14 However, RASM-expressing L341S-FRNK demonstrated significantly greater migratory activity compared with wtFRNK-expressing cells for both chemoattractants.…”

Section: Resultsmentioning

confidence: 89%

“…In a previous report, 14 the inhibitory effects of FRNK on VSMC spreading and migration were highly dependent on its phosphorylation at Y168 but not at Y232. The overexpression of a green fluorescent protein (GFP)–tagged nonphosphorylatable mutant (Y168F-FRNK) markedly abrogated FRNK’s inhibition of cell spreading after cell attachment and also restored VSMC migration in a 3D Boyden chamber assay.…”

mentioning

confidence: 77%

“…14 We used a previously described point mutationin the FA targeting domain of FAK to interfere with the paxillin-FRNK interaction. This mutation is located within the fourth α-helix of the FA targeting α-helical bundle of FRNK, precisely within residues that compose the second of 2 hydrophobic patches (HP) (ie, HP1 and HP2) involved in paxillin binding.…”

Section: Discussionmentioning

confidence: 99%

“…FRNK is selectively expressed in vascular smooth muscle cells (VSMCs), with high levels found after arterial injury. 12–14 FRNK is thought to act as a dominant-negative inhibitor of full-length FAK in cultured cells. FRNK inhibits cell spreading of chick embryo fibroblasts, 15 inhibits migration of endothelial and rat aortic smooth muscle cells (RASMs), 12,14,16 and reduces proliferation of VSMCs.…”

mentioning

confidence: 99%

“…12–14 FRNK is thought to act as a dominant-negative inhibitor of full-length FAK in cultured cells. FRNK inhibits cell spreading of chick embryo fibroblasts, 15 inhibits migration of endothelial and rat aortic smooth muscle cells (RASMs), 12,14,16 and reduces proliferation of VSMCs. 12,17 Previous laboratory studies 14,18–21 have demonstrated that FRNK inhibits FAK-dependent signaling in both cardiomyocytes and VSMCs.…”

mentioning

confidence: 99%

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FRNK Inhibition of Focal Adhesion Kinase–Dependent Signaling and Migration in Vascular Smooth Muscle Cells

Koshman

Kim

Chu

et al. 2010

ATVB

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Objective To examine whether interference with FRNK targeting to focal adhesions (FAs) affects its inhibitory activity and tyrosine phosphorylation. Methods and Results Focal adhesion kinase and its autonomously expressed C-terminal inhibitor, focal adhesion kinase–related nonkinase (FRNK), regulate vascular smooth muscle cell (VSMC) signaling and migration. FRNK-paxillin binding was reduced by a point mutation in its FA targeting domain (L341S-FRNK). Green fluorescent protein–tagged wild type and L341S-FRNK were then adenovirally expressed in VSMCs. L341S-FRNK targeted to VSMC FAs, despite previous studies in other cell types. L341S-FRNK affected FA binding kinetics (assessed by total internal reflection fluorescnece [TIRF] microscopy and fluorescence recovery after photobleaching [FRAP]) and reduced its steady-state paxillin interaction (determined by coimmunoprecipitation). Both wt-FRNK and L341S-FRNK lowered basal and angiotensin II–stimulated focal adhesion kinase, paxillin, and extracellular signal–regulated kinase 1/2 phosphorylation. However, the degree of inhibition was significantly reduced by L341S-FRNK. L341S-FRNK also demonstrated significantly greater migratory activity compared with wt-FRNK–expressing VSMCs. Angiotensin II–induced Y168 phosphorylation was Src dependent, as evident by a significant reduction in Y168 phosphorylation by the Src family kinase inhibitor PP2 is 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2). Surprisingly, Y168 phosphorylation was unaffected by its targeting. Furthermore, Y232 phosphorylation increased approximately 3-fold in L341S-FRNK, which was less sensitive to PP2. Conclusion FRNK inhibition of VSMC migration requires both FA targeting and Y168 phosphorylation by Src family kinases. FRNK-Y232 phosphorylation occurs outside of FAs, probably by a PP2-insensitive kinase.

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Section: Resultsmentioning

confidence: 89%

mentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%