Platelet-derived growth factor-BB (PDGF-BB) regulation of migration and focal adhesion kinase phosphorylation in rabbit aortic vascular smooth musclecells: roles of phosphatidylinositol 3-kinase and mitogen-activated protein kinases
R. Cospedal et al., Platelet-derived growth factor-BB (PDGF-BB) regulation of migration and focal adhesion kinase phosphorylation in rabbit aortic vascular smooth musclecells: roles of phosphatidylinositol 3-kinase and mitogen-activated protein kinases, CARDIO RES, 41(3), 1999, pp. 708-721
Citations number
55
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Objective: Phosphatidylinositol 3'-kinase (PI3-kinase) is implicated in cel
l migration and focal adhesion kinase (FAK) phosphorylation. In contrast, i
t has been proposed that mitogen-activated protein (MAP) kinases are essent
ial for proliferation but may be dissociated from chemotactic signalling. W
e investigated the roles of PI3-kinase and p42/p44 MAP kinases in cell migr
ation and FAK tyrosine phosphorylation induced by platelet-derived growth f
actor-BB (PDGF-BB)in rabbit aortic vascular smooth muscle cells (VSMCs). Th
e roles of PI3-kinase and MAP kinase pathways in the chemotactic response t
o insulin-like growth factor-I (IGF-I) were also examined. Methods: The rol
es of PI3-kinase and p42/p44 MAP kinases were assessed using the PIS-kinase
inhibitors, wortmannin and LY294002, and an inhibitor of MAP kinase kinase
, PD98059. PI3-kinase activity was measured by phosphatidylinositol phospho
rylation in anti-phosphotyrosine immunoprecipitates and by thin layer chrom
atography of phosphorylated products. Phosphorylation was assessed by immun
oprecipitation with anti-phosphotyrosine antibodies and Western blotting wi
th FAK-specific antibody. Migration was evaluated in a chemotaxis chamber u
sing polycarbonate filters with an 8-mm pore size. Results: Neither wortman
nin nor LY294002 significantly reduced PDGF-BB stimulation of FAK tyrosine
phosphorylation, chemotaxis or immunofluorescent staining of focal adhesion
s in VSMCs. PD98059, a specific inhibitor of MAP kinase activation, did not
inhibit FAK tyrosine phosphorylation but markedly inhibited the migratory
response of VSMCs to PDGF-EB. IGF-I also stimulated migration of VSMCs, and
, relative to the effect of PDGF-BE, induced smaller increases in PIS-kinas
e and MAP kinase activities. Both wortmannin and PD98059 partially inhibite
d the migratory response to IGF-I. Conclusions: PDGF-BB stimulation of both
FAK tyrosine phosphorylation and migration in VSMCs are not dependent on a
ctivation of PI3-kinase. While PDGF-BB stimulation of FAK tyrosine phosphor
ylation is not dependent on p42/p44 MAP kinase activation, PDGF-BB and IGF-
I bath stimulate p42/p44 MAP kinase activity and the chemotactic response t
o these factors is partially dependent on MAP kinase activation. (C) 1999 E
lsevier Science B.V. All rights reserved.