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Rho‐kinase (ROCK) mediates PAK1 activation by angiotensin II in vascular smooth muscle cells (VSMCs).
Author(s) -
Higuchi Sadaharu,
Ohtsu Haruhiko,
Woolfolk Elethia A,
Motley Evangeline D,
Oe Tomoyuki,
Eguchi Satoru
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1244-c
Subject(s) - angiotensin ii , vascular smooth muscle , signal transduction , pak1 , phosphorylation , microbiology and biotechnology , rho associated protein kinase , protein kinase c , angiotensin ii receptor type 1 , chemistry , kinase , biology , receptor , biochemistry , endocrinology , smooth muscle
Many distinct signal transduction cascades may coordinate vascular remodeling induced by a potent cardiovascular pathogen, angiotensin II (AngII). AngII has been shown to stimulate p21‐activated kinase (PAK)1 to activate JNK, a critical component of the signaling pathways implicated in growth and migration of VSMCs. Recently, we have shown that PAK1 activation by AngII exists downstream of PKCδ and that the PKCδ/Rho/ROCK pathway leads to JNK activation by AngII in VSMCs. Here, we have tested our hypothesis that there is a critical signal cross‐talk between PAK1 and the Rho/ROCK cascade in VSMCs stimulated with AngII. AngII (100 nM) rapidly (5 min) phosphorylated PAK1 Ser 194/204 , and an AT 1 receptor antagonist completely inhibited the phosphorylation in VSMCs. Infection of VSMCs with an adenovirus encoding dominant negative (dn) Rho inhibited PAK1 phosphorylation by AngII. Moreover, pretreatment with YM‐27632, a ROCK inhibitor, blocked PAK1 phosphorylation induced by AngII in VSMCs. In addition, proteomics approach was used to study PAK1 activation. An affinity pull‐down assay using PAK1‐GST fusion protein with AngII stimulation revealed two markedly inducible PAK1 associatable protein bands that were subjected to a LC/MS analysis after tryptic digestion. Using a protein database search, we identified several novel candidate proteins with signal transduction properties which possibly interact with PAK1 after AngII stimulation. These data suggest that PAK1 and novel PAK1 interacting proteins exist downstream of Rho/ROCK activation induced by AngII in VSMCs which may play critical roles in vascular remodeling.