Evidence for a functional association between phosphatidylinositol 3-kinase and c-src in the spreading response of osteoclasts to colony-stimulating factor-1.
Osteoclasts are bone-resorbing cells whose normal function depends in part upon their ability to migrate over the bone surface to initiate new sites of bone resorption. The growth factor/cytokine, colony-stimulating factor-1 (CSF-1), potently stimulates osteoclast motility, in a c-src-dependent fashion. The intracellular signaling molecules that participate with c-src in CSF-1-induced remodeling of the osteoclast cytoskeleton have not been identified. Here we demonstrate, using the inhibitors wortmannin and LY294002, that activation of phosphatidylinositol 3-kinase (PI3-K) is required for CSF-1-induced spreading in osteoclasts. After CSF-1 treatment of osteoclast-like cells, PI3-K activity associated with the CSF-1 receptor c-fms, is increased, and the 85-kDa regulatory subunit of PI3-K and c-src coimmunoprecipitate. CSF-1 induces redistribution of PI3-K to the periphery of the cell. The association between p85 and c-src is due in part to a direct interaction between the proline-rich sequences of p85 and the SH3 domain of c-src. In vitro, the c-src SH3 domain stimulates PI3-K activity. Taken together, the current data suggest that c-src, via its SH3 domain, may participate in CSF-1-induced activation of PI3-K and that PI3-K and c-src are in the signaling pathway that subserves CSF-1-induced cytoskeletal changes in osteoclasts.
Grey
A
A
Section of Endocrinology, Yale University, New Haven, Connecticut 06520, USA.
Chen
Y
Y
Paliwal
I
I
Carlberg
K
K
Insogna
K
K
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002465:Cell Movement; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007163:Immunosorbent Techniques; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D010010:Osteoclasts / Q000166:cytology*; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011392:Proline; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D051381:Rats; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D000077191:Wortmannin; D018909:src Homology Domains
D000730:Androstadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D016173:Macrophage Colony-Stimulating Factor; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011392:Proline; D016392:Proto-Oncogene Proteins pp60(c-src); D016186:Receptor, Macrophage Colony-Stimulating Factor; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one