Expression of Src family kinases and their putative substrates in the human preosteoclastic cell line FLG 29.1.
Several lines of evidence suggest that the c-Src tyrosine kinase has a specific role in bone-resorbing osteoclasts. To investigate this further, we examined the expression of c-Src, its kinase family members, and their putative substrates in the human leukemia cell line FLG 29.1. Western blot analysis with specific antibodies against Src family members showed expression of Src, Fyn, and Lyn, lower levels of Yes and Hck, and the absence of Lck tyrosine kinase. During a 3-day treatment with phorbol 12-myristate, 13-acetate (PMA), which induces differentiation of FLG 29.1 cells toward an osteoclast-like phenotype, the levels of Src and Fyn increased and the levels of Lyn decreased. In a similar leukemia cell line, HL-60, Src protein was not constitutively expressed and not induced by PMA treatment, which leads to monocytic differentiation. PMA treatment of FLG 29.1 cells induced a strong increase in the expression of p120 Cbl and Pyk2 kinase, which are putative Src substrates. Pyk2 phosphorylation increased upon adherence of FLG 29.1 cells to fibronectin and to ST2 stromal cells. The expression of other Src substrates and interacting proteins, such as p120 Cas, p130 Cas, vinculin, Fak kinase, and the p85 phosphatidylinositol 3-kinase subunit either did not change or slightly increased during PMA treatment. The elevated total protein tyrosine phosphorylation in PMA-treated FLG 29.1 cells was abolished by herbimycin A, a Src inhibitor. These data are consistent with the proposed role of Src in the osteoclastic function and support the use of FLG 29.1 cells as a model to study Src substrates in the cells of the osteoclastic lineage.
Jeschke
M
M
Novartis Pharma AG, Research Bone Metabolism, Basel, Switzerland.
Brandi
M L
ML
Susa
M
M
D015153:Blotting, Western; D000081247:CSK Tyrosine-Protein Kinase; D051177:Catenins; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D050719:Crk-Associated Substrate Protein; D004591:Electrophoresis, Polyacrylamide Gel; D000091344:Filaggrin Proteins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D015971:Gene Expression Regulation, Enzymologic; D018922:HL-60 Cells; D006801:Humans; D010010:Osteoclasts / Q000187:drug effects / Q000201:enzymology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000378:metabolism; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D013234:Stem Cells / Q000187:drug effects / Q000201:enzymology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism; D016596:Vinculin / Q000378:metabolism; D019061:src-Family Kinases; D000095002:Delta Catenin
D000081247:CSK Tyrosine-Protein Kinase; D051177:Catenins; D015815:Cell Adhesion Molecules; D050719:Crk-Associated Substrate Protein; D000091344:Filaggrin Proteins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D011505:Protein-Tyrosine Kinases; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D013755:Tetradecanoylphorbol Acetate; D014443:Tyrosine; D016596:Vinculin; D019061:src-Family Kinases; D000095002:Delta Catenin; C493841:BCAR1 protein, human; C000717249:FLG protein, human; C496050:PTK2 protein, human; C000631346:CSK protein, human; C000722347:CTNND1 protein, human