TY - JOUR
T1 - Agonist-stimulated cytoskeletal reorganization and signal transduction at focal adhesions in vascular smooth muscle cells require c-Src
AU - Ishida, Takafumi
AU - Ishida, Mari
AU - Suero, James
AU - Takahashi, Masafumi
AU - Berk, Bradford C.
PY - 1999/3
Y1 - 1999/3
N2 - Thrombin and angiotensin II (angII) have trophic properties as mediators of vascular remodeling. Focal adhesions and actin cytoskeleton are involved in cell growth, shape, and movement and may be important in vascular remodeling. To characterize mechanisms by which thrombin and angII modulate vessel structure, we studied the effects of these G protein-coupled receptor ligands on focal adhesions in vascular smooth muscle cells (VSMCs). Both thrombin and angII stimulated bundling of actin filaments to form stress fibers, assembly of focal adhesions, and protein tyrosine phosphorylation at focal adhesions, such as p130Cas, paxillin, and tensin. To test whether c- Src plays a critical role in focal adhesion rearrangement, we analyzed cells with altered c-Src activity by retroviral transduction of wild-type (WT) and kinase-inactive (KI) c-Src into rat VSMCs, and by use of VSMCs from WT (src(+/+)) and Src-deficient (src(-/-)) mice. Tyrosine phosphorylation of Cas, paxillin, and tensin were markedly decreased in VSMCs expressing KI-Src and in src(-/-) VSMCs. Expression of KI-Src did not inhibit stress fiber formation by thrombin. Surprisingly, actin bundling was markedly decreased in VSMCs from src(-/-) mice both basally and after thrombin stimulation, compared with src(+/+) mice. We also studied the effect of KI-Src and WT-Src on VSMC spreading. Expression of KI-Src reduced the rate of VSMC spreading on collagen, whereas WT-Src enhanced cell spreading. In conclusion, c-Src plays a critical role in agonist-stimulated cytoskeletal reorganization and signal transduction at focal adhesions in VSMCs. c-Src kinase activity is required for the cytoskeletal turnover that occurs in cell spreading, whereas c-Src appears to regulate actin bundling via a kinase-independent mechanism.
AB - Thrombin and angiotensin II (angII) have trophic properties as mediators of vascular remodeling. Focal adhesions and actin cytoskeleton are involved in cell growth, shape, and movement and may be important in vascular remodeling. To characterize mechanisms by which thrombin and angII modulate vessel structure, we studied the effects of these G protein-coupled receptor ligands on focal adhesions in vascular smooth muscle cells (VSMCs). Both thrombin and angII stimulated bundling of actin filaments to form stress fibers, assembly of focal adhesions, and protein tyrosine phosphorylation at focal adhesions, such as p130Cas, paxillin, and tensin. To test whether c- Src plays a critical role in focal adhesion rearrangement, we analyzed cells with altered c-Src activity by retroviral transduction of wild-type (WT) and kinase-inactive (KI) c-Src into rat VSMCs, and by use of VSMCs from WT (src(+/+)) and Src-deficient (src(-/-)) mice. Tyrosine phosphorylation of Cas, paxillin, and tensin were markedly decreased in VSMCs expressing KI-Src and in src(-/-) VSMCs. Expression of KI-Src did not inhibit stress fiber formation by thrombin. Surprisingly, actin bundling was markedly decreased in VSMCs from src(-/-) mice both basally and after thrombin stimulation, compared with src(+/+) mice. We also studied the effect of KI-Src and WT-Src on VSMC spreading. Expression of KI-Src reduced the rate of VSMC spreading on collagen, whereas WT-Src enhanced cell spreading. In conclusion, c-Src plays a critical role in agonist-stimulated cytoskeletal reorganization and signal transduction at focal adhesions in VSMCs. c-Src kinase activity is required for the cytoskeletal turnover that occurs in cell spreading, whereas c-Src appears to regulate actin bundling via a kinase-independent mechanism.
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U2 - 10.1172/JCI4189
DO - 10.1172/JCI4189
M3 - Article
C2 - 10079099
AN - SCOPUS:0033559439
SN - 0021-9738
VL - 103
SP - 789
EP - 797
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 6
ER -