Receptor activator of NF-kappa B ligand stimulates recruitment of SHP-1 to the complex containing TNFR-associated factor 6 that regulates osteoclastogenesis.

Receptor activator of NF-kappaB ligand (RANKL) is essential for differentiation and function of osteoclasts. The negative signaling pathways downstream of RANKL are not well characterized. By retroviral transduction of RAW264.7 cells with a dominant negative Src homology 2 domain-containing phosphatase-1 (SHP-1)(C453S), we studied the role of tyrosine phosphatase SHP-1 in ...
RANKL-induced osteoclastogenesis. Over-expression of SHP-1(C453S) significantly enhanced the number of tartrate-resistant acid phosphatase-positive multinuclear osteoclast-like cells in response to RANKL in a dose-dependent manner. RANKL induced the recruitment of SHP-1 to a complex containing TNFR-associated factor (TRAF)6. GST pull down experiments indicated that the association of SHP-1 with TRAF6 is mediated by SHP-1 lacking the two Src homology 2 domains. RANKL-stimulated IkappaB-alpha phosphorylation, IkappaB-alpha degradation and DNA binding ability of NF-kappaB were increased after over-expression of SHP-1(C453S). However, RANKL-induced phosphorylation of mitogen-activated protein kinases, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase, was unchanged. In addition, SHP-1 regulated RANKL-stimulated tyrosine phosphorylation of p85 subunit of phosphatidylinositol 3 kinase and the phosphorylation of Akt. Increased numbers of osteoclasts contribute to severe osteopenia in Me(v)/Me(v) mice due to mutation of SHP-1. Like RAW264.7 cells expressing SHP-1(C453S), the bone marrow macrophages of Me(v)/Me(v) mice generated much more osteoclast-like cells than that of littermate controls in response to RANKL. Furthermore compared with controls, RANKL induces enhanced association of TRAF6 and RANK in both RAW264.7 cells expressing SHP-1(C453S) and bone marrow macrophages from Me(v)/Me(v) mice. Therefore, SHP-1 plays a role in signals downstream of RANKL by recruitment to the complex containing TRAF6 and these observations may help to understand the mechanism of osteoporosis in Me(v)/Me(v) mice.
Mesh Terms:
Animals, Carrier Proteins, Cell Differentiation, Cell Line, Cysteine, Genetic Vectors, Glycoproteins, Intracellular Signaling Peptides and Proteins, Ligands, Macrophages, Membrane Glycoproteins, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, NF-kappa B, Osteoclasts, Osteoprotegerin, Phosphatidylinositol 3-Kinases, Phosphorylation, Protein Phosphatase 1, Protein Subunits, Protein Transport, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Protein Tyrosine Phosphatases, Protein-Serine-Threonine Kinases, Proteins, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-akt, RANK Ligand, Receptor Activator of Nuclear Factor-kappa B, Receptors, Cytoplasmic and Nuclear, Receptors, Tumor Necrosis Factor, Retroviridae, Serine, TNF Receptor-Associated Factor 6, Transduction, Genetic, Tyrosine, Up-Regulation, src Homology Domains
J. Immunol.
Date: Oct. 01, 2003
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