Colony-stimulating factor-1 induces cytoskeletal reorganization and c-src-dependent tyrosine phosphorylation of selected cellular proteins in rodent osteoclasts

• Published in: The Journal of clinical investigation Vol. 100; no. 10; pp. 2476 - 2485
• Main Authors: Insogna, K L, Sahni, M, Grey, A B, Tanaka, S, Horne, W C, Neff, L, Mitnick, M, Levy, J B, Baron, R
• Format: Journal Article
• Language: English
• Published: United States 15.11.1997
• Subjects: Amino Acid Sequence; Animals; Animals, Newborn; Cell Movement - drug effects; Cells, Cultured; Cytoskeleton - drug effects; Cytoskeleton - ultrastructure; Kinetics; Macrophage Colony-Stimulating Factor - pharmacology; Molecular Sequence Data; Osteoclasts - drug effects; Osteoclasts - physiology; Osteoclasts - ultrastructure; Peptides - chemistry; Peptides - metabolism; Phosphoproteins - isolation & purification; Phosphoproteins - metabolism; Phosphorylation; Phosphotyrosine - metabolism; Polymerase Chain Reaction; Proto-Oncogene Proteins pp60(c-src) - deficiency; Proto-Oncogene Proteins pp60(c-src) - metabolism; Rats; Space life sciences; src-Family Kinases - metabolism; Substrate Specificity
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/jci119790

Colony-stimulating factor-1 (CSF-1) stimulates motility and cytoplasmic spreading in mature osteoclasts. Therefore, we examined the cellular events and intracellular signaling pathways that accompany CSF-1-induced spreading in normal osteoclasts. To explore the role c-src plays in these processes, we also studied osteoclasts prepared from animals with targeted disruption of the src gene. In normal osteoclasts, CSF-1 treatment induces rapid cytoplasmic spreading, with redistribution of F-actin from a well-delineated central attachment ring to the periphery of the cell. CSF-1 increases membrane phosphotyrosine staining in osteoclasts and induces the phosphorylation of several cellular proteins in cultured, osteoclast-like cells, including c-fms, c-src, and an 85-kD Grb2-binding protein. Src kinase activity is increased threefold after CSF-1 treatment. In src- cells, no attachment ring is present, and CSF-1 fails to induce spreading or a change in the pattern of F-actin distribution. Although c-fms becomes phosphorylated after CSF-1 treatment, the 85-kD protein is significantly less phosphorylated in src- osteoclast-like cells. These results indicate that c-src is critical for the normal cytoskeletal architecture of the osteoclast, and, in its absence, the spreading response induced by CSF-1 is abrogated, and downstream signaling from c-fms is altered.