Absence of Dap12 and the αvβ3 integrin causes severe osteopetrosis.

ABSTRACT: In vitro, ligand occupancy of αvβ3 integrin induces phosphorylation of Dap12, which is essential for osteoclast function. Like mice deleted of only αvβ3, Dap12(-/-) mice exhibited a slight increase in bone mass, but Dap12(-/-) mice, lacking another ITAM protein, FcRγ, were severely osteopetrotic. The mechanism by which FcRγ compensates for Dap12 deficiency is unknown. We find that co-deletion of FcRγ did not exacerbate the skeletal phenotype of β3(-/-) mice. In contrast, β3/Dap12 double-deficient (DAP/β3(-/-)) mice (but not β1/Dap12 double-deficient mice) were profoundly osteopetrotic, reflecting severe osteoclast dysfunction relative to those lacking αvβ3 or Dap12 alone. Activation of OSCAR, the FcRγ co-receptor, rescued Dap12(-/-) but not DAP/β3(-/-)osteoclasts. Thus, the absence of αvβ3

SUBMITTER: Zou W 

PROVIDER: S-EPMC4284236 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature