Role of c-Abl tyrosine kinase in smooth muscle cell migration.
c-Abl is a nonreceptor protein tyrosine kinase that has a role in regulating smooth muscle cell proliferation and contraction. The role of c-Abl in smooth muscle cell migration has not been investigated. In the present study, c-Abl was found in the leading edge of smooth muscle cells. Knockdown of c-Abl by RNA interference attenuated smooth muscle cell motility as evidenced by time-lapse microscopy. Furthermore, the actin-associated proteins cortactin and profilin-1 (Pfn-1) have been implicated in cell migration. In this study, cell adhesion induced cortactin phosphorylation at Tyr-421, an indication of cortactin activation. Phospho-cortactin and Pfn-1 were also found in the cell edge. Pfn-1 directly interacted with cortactin in vitro. Silencing of c-Abl attenuated adhesion-induced cortactin phosphorylation and Pfn-1 localization in the cell edge. To assess the role of cortactin/Pfn-1 coupling, we developed a cell-permeable peptide. Treatment with the peptide inhibited the interaction of cortactin with Pfn-1 without affecting cortactin phosphorylation. Moreover, treatment with the peptide impaired the recruitment of Pfn-1 to the leading edge and cell migration. Finally, β1-integrin was required for the recruitment of c-Abl to the cell edge. Inhibition of actin dynamics impaired the spatial distribution of c-Abl. These results suggest that β1-integrin may recruit c-Abl to the leading cell edge, which may regulate cortactin phosphorylation in response to cell adhesion. Phosphorylated cortactin may facilitate the recruitment of Pfn-1 to the cell edge, which promotes localized actin polymerization, leading edge formation, and cell movement. Conversely, actin dynamics may strengthen the recruitment of c-Abl to the leading edge.
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York.
Rachel A
RA
Cleary
Ruping
R
Wang
Omar
O
Waqar
Harold A
HA
Singer
Dale D
DD
Tang
D000818:Animals; D026481:Blotting, Far-Western; D002448:Cell Adhesion; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D051356:Cortactin / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D019012:Integrin beta1 / Q000235:genetics / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000201:enzymology* / Q000502:physiology*; D010766:Phosphorylation; D051304:Profilins / Q000235:genetics / Q000378:metabolism; D016315:Proto-Oncogene Proteins c-abl / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014161:Transduction, Genetic
C495868:CTTN protein, human; D051356:Cortactin; D019012:Integrin beta1; C495738:PFN1 protein, human; D051304:Profilins; D016315:Proto-Oncogene Proteins c-abl
actin cytoskeleton; adapter protein; cell migration; smooth muscle; tyrosine kinase