VASP phosphorylation at serine239 regulates the effects of NO on smooth muscle cell invasion and contraction of collagen.
Nitric oxide triggers cGMP-dependent kinase-mediated phosphorylation of the actin regulator vasodilator-stimulated phosphoprotein (VASP) at residue serine239. The function of this phosphorylation for smooth muscle cell (SMC) adhesion, spreading, matrix contraction, and invasion is not well understood. We reconstituted VASP deficient SMC with wild-type VASP (wt-VASP) or VASP mutants that mimic "locked" serine239 phosphorylation (S239D-VASP) or "blocked" serine239 phosphorylation (S239A-VASP). Collagen gel contraction was reduced in S239D-VASP compared to S239A-VASP and wt-VASP expressing cells and nitric oxide (NO) stimulation decreased gel contraction of wt-VASP reconstituted SMC. Invasion of collagen was enhanced in S239D-VASP and NO-stimulated wild-type SMCs compared to S239A-VASP expressing cells. Expression of S239D-VASP impaired SMC attachment to collagen, reduced the number of membrane protrusions, and caused cell rounding compared to expression of S239A-VASP. Treatment of wt-VASP reconstituted SMCs with NO exerted similar effects as expression of S239D-VASP. As unstimulated cells were spreading on collagen S239A-VASP and wt-VASP localized to actin fibers whereas S239D-VASP was enriched in the cytosol. NO interferes with SMC invasion and contraction of collagen matrices. This requires phosphorylation of VASP on serine239, which reduces VASP binding to actin fibers. These findings support the conclusion that VASP phosphorylation at serine239 regulates cytoskeleton remodeling.
Defawe
Olivier D
OD
Department of Surgery, University of Washington, Seattle, Washington 98109, USA.
Kim
Sarah
S
Chen
Lihua
L
Huang
Daming
D
Kenagy
Richard D
RD
Renné
Thomas
T
Walter
Ulrich
U
Daum
Günter
G
Clowes
Alexander W
AW
D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000172:deficiency / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D022081:Cell Surface Extensions / Q000187:drug effects / Q000378:metabolism; D003094:Collagen / Q000378:metabolism*; D005782:Gels; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins / Q000172:deficiency / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D010750:Phosphoproteins / Q000172:deficiency / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D000098662:Vasodilator-Stimulated Phosphoprotein
D000199:Actins; D015815:Cell Adhesion Molecules; D005782:Gels; D008840:Microfilament Proteins; D050505:Mutant Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D010768:Phosphoserine; D009569:Nitric Oxide; D003094:Collagen