title: Vav3 regulates osteoclast function and bone mass.
abstract: Osteoporosis, a leading cause of morbidity in the elderly, is characterized by progressive loss of bone mass resulting from excess osteoclastic bone resorption relative to osteoblastic bone formation. Here we identify Vav3, a Rho family guanine nucleotide exchange factor, as essential for stimulated osteoclast activation and bone density in vivo. Vav3-deficient osteoclasts show defective actin cytoskeleton organization, polarization, spreading and resorptive activity resulting from impaired signaling downstream of the M-CSF receptor and alpha(v)beta3 integrin. Vav3-deficient mice have increased bone mass and are protected from bone loss induced by systemic bone resorption stimuli such as parathyroid hormone or RANKL. Moreover, we provide genetic and biochemical evidence for the role of Syk tyrosine kinase as a crucial upstream regulator of Vav3 in osteoclasts. Thus, Vav3 is a potential new target for antiosteoporosis therapy.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Roberta
authors.initials: R
authors.lastname: Faccio
authors.forename: Steven L
authors.initials: SL
authors.lastname: Teitelbaum
authors.forename: Keiko
authors.initials: K
authors.lastname: Fujikawa
authors.forename: Jean
authors.initials: J
authors.lastname: Chappel
authors.forename: Alberta
authors.initials: A
authors.lastname: Zallone
authors.forename: Victor L
authors.initials: VL
authors.lastname: Tybulewicz
authors.forename: F Patrick
authors.initials: FP
authors.lastname: Ross
authors.forename: Wojciech
authors.initials: W
authors.lastname: Swat
mesh_terms: D000818:Animals; D015519:Bone Density; D001862:Bone Resorption / Q000503:physiopathology; D002352:Carrier Proteins / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors / Q000502:physiology; D039302:Integrin alphaVbeta3 / Q000502:physiology; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000502:physiology*; D051567:Proto-Oncogene Proteins c-vav; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D012234:Rho Factor / Q000502:physiology; D051746:ZAP-70 Protein-Tyrosine Kinase
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D039302:Integrin alphaVbeta3; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D012234:Rho Factor; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; C496622:Vav3 protein, mouse; D016173:Macrophage Colony-Stimulating Factor; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497262:Zap70 protein, mouse