NO-dependent osteoclast motility: reliance on cGMP-dependent protein kinase I and VASP.
The osteoclast degrades bone in cycles; between cycles, the cell is motile. Resorption occurs by acid transport into an extracellular compartment defined by an alphavbeta3 integrin ring. NO has been implicated in the regulation of bone turnover due to stretch or via estrogen signals, but a specific mechanism linking NO to osteoclastic activity has not been described. NO stimulates osteoclast motility, and at high concentrations NO causes detachment and terminates resorption. Here we demonstrate that NO regulates attachment through the cGMP-dependent protein kinase I (PKG I) via phosphorylation of the intermediate protein VASP. VASP colocalized with the alphavbeta3 ring in stationary cells, but alternating bands of VASP and alphavbeta3 occurred when motility was induced by NO donors or cGMP. Redistribution of VASP correlated with its phosphorylation. Dependency of NO-induced motility on PKG I and on VASP was shown by siRNA knockdown of each protein. VASP knockdown also altered distribution of alphavbeta3 at the attachment site. We conclude that PKG I and VASP are essential for reorganization of attachment and cytoplasmic proteins in motility induced by NO or by cGMP.
Yaroslavskiy
Beatrice B
BB
Department of Pathology, University of Pittsburgh and Veteran's Affairs Medical Center, Pittsburgh, PA 15243, USA.
Zhang
Yongjun
Y
Kalla
Sara E
SE
García Palacios
Verónica
V
Sharrow
Allison C
AC
Li
Yanan
Y
Zaidi
Mone
M
Wu
Chuanyue
C
Blair
Harry C
HC
D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism / Q000494:pharmacology; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism / Q000494:pharmacology; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D000098662:Vasodilator-Stimulated Phosphoprotein
D015815:Cell Adhesion Molecules; D039302:Integrin alphaVbeta3; D008840:Microfilament Proteins; D020030:Nitric Oxide Donors; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D009569:Nitric Oxide; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; C569718:PRKG1 protein, human; D006152:Cyclic GMP