Arrestins regulate cell spreading and motility via focal adhesion dynamics.
Bottom Line: Clathrin exhibited decreased dynamics near FA in arrestin-deficient cells.In contrast to wild-type arrestins, mutants deficient in clathrin binding did not rescue the phenotype.Collectively the data indicate that arrestins are key regulators of FA disassembly linking microtubules and clathrin.
Affiliation: Department of Pharmacology, Vanderbilt University, Nashville, TN 37232.Show MeSH
Related in: MedlinePlus
Mentions: FAs are key signaling hubs that recruit many proteins to the site of integrin activation (Sastry and Burridge, 2000; Gieger et al., 2009). Arrestins bind Src, ERK1/2, and JNK3 (Gurevich and Gurevich, 2006b), all of which regulate FAs (Webb et al., 2004; Huveneers and Danen, 2009). Rapid assembly and disassembly of these complexes plays a central role in cell adhesion and migration. On the basis of the decreased migration and increased adhesion of DKO cells, we hypothesized that FA dynamics is likely affected. To test this idea, we stained cells with rhodamine–phalloidin and an anti-paxillin antibody to visualize actin cytoskeleton and FAs, respectively. In WT MEFs, we observed a small number of FAs located primarily at the edges of cells plated on FN and virtually none in cells plated on PDL (Figure 3A). Strikingly, in DKO cells, the number of FAs was dramatically increased. In addition, FAs in DKO MEFs were present not only at the periphery but also throughout the cell on both FN and PDL (Figure 3A). Immunostaining for active phospho-paxillin (P-Y118) and phospho-FAK (P-Y397) also revealed similar differences in FA number and localization between WT and DKO cells (Supplemental Figure S2, A–C). Of importance, in single-knockout cells, the FA pattern was similar to WT on PDL, but cells lacking either arrestin had more FAs on FN, although not as many as DKO MEFs (Supplemental Figure S3, A–C). These data suggest that both arrestin-2 and -3 participate in the regulation of FAs and cell size, and the magnitude of DKO phenotype reflects the absence of both arrestins.
Affiliation: Department of Pharmacology, Vanderbilt University, Nashville, TN 37232.