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BAY 41‐2272 increases VASP phosphorylation via increases in both cAMP and cGMP in rat primary VSMCs
Author(s) -
Adderley Shaquria,
Joshi Chintamani,
Martin Danielle,
Mooney Shayna,
Tulis David
Publication year - 2011
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.25.1_supplement.1008.4
Subject(s) - bay , phosphorylation , protein kinase c , microbiology and biotechnology , kinase , chemistry , protein kinase a , biology , civil engineering , engineering
We recently reported that the guanylate cyclase agonist, BAY 41‐2272 (BAY), has anti‐proliferative properties in rat A7R5 vascular smooth muscle cells (VSMCs); however, its mechanism of action is not clear. Here we sought to elucidate the mechanisms of BAY‐mediated growth inhibition and we hypothesize that BAY inhibits VSMC proliferation through selective phosphorylation of vasodilator‐activated serum phosphoprotein (VASP). In rat primary VSMCs, BAY increased cAMP (~9500%,1nM, 30″) and cGMP (233%,100nM, 15Prime;), and at 10μM significantly increased VASP Ser239 and VASP Ser157 phosphorylation (pSer 239 and pSer 157 ), respective markers for active PKG and PKA. The PKA inhibitor PKI augmented BAY‐induced pSer 239 and pSer 157 , whereas the PKG inhibitor DT2 increased pSer 239 but had no effect at pSer 157 . These findings suggest that BAY operates through both PKA and PKG to phosphorylate VASP Ser239 and through PKA to phosphorylate VASP Ser157 . Interestingly, the PKC inhibitor Calphostin C increased BAY‐induced pSer 239 but had no effect on pSer 157 , again suggesting involvement of multiple kinases in BAY‐mediated pSer 239 . In comparison, in the presence of a cGMP analog, 8Br‐cGMP, only DT2 increased pSer 239 , suggesting that PKC and PKA phosphorylation induced by BAY are via increases in cAMP. These data suggest that BAY induces differential phosphorylation of VASP by cross‐talk between the cAMP and cGMP pathways.