ERK activation and alpha v beta 3 integrin signaling through Shc recruitment in response to mechanical stimulation in human osteoblasts.
Osteoblast growth and differentiation are critical processes for bone development and maintenance, and are regulated by both humoral and mechanical factors. Humoral (hormonal) factors can affect gene transcription via MAPkinases, e.g., extracellular signal-regulated kinase (ERK). We studied whether the ERK pathway is also involved in processing mechanical inputs in human bone cells. Exposing MG63 cells to physiologically relevant levels of fluid flow resulted in ERK phosphorylation. Genistein blocked this response, indicating that it is dependent on tyrosine phosphorylation. Furthermore, alpha v beta 3 integrins were activated in response to fluid flow, as shown by recruitment of adaptor molecule Shc and clustering of alpha v beta 3 in focal adhesion-like structures. Antibodies blocking formation of beta 1 or beta 3 integrin-matrix interactions or RGD peptides could not inhibit fluid flow-induced ERK phosphorylation, suggesting that formation of new integrin-matrix interactions is not essential for this response and that other upstream mechanosensors regulate induction of ERK phosphorylation in response to fluid flow in human bone cells.
Weyts
F A A
FA
Department of Orthopaedics, Department of Internal Medicine, Erasmus University Medical Center Rotterdam, 3000 DR Rotterdam, The Netherlands. weyts@ortho.fgg.eur.nl
Li
Y S
YS
van Leeuwen
J
J
Weinans
H
H
Chien
S
S
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D002460:Cell Line; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D010006:Osteoblasts / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011506:Proteins / Q000378:metabolism*; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D013314:Stress, Mechanical; D013997:Time Factors; D014158:Transcription, Genetic
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D004791:Enzyme Inhibitors; D039302:Integrin alphaVbeta3; D009842:Oligopeptides; D011506:Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C047981:arginyl-glycyl-aspartic acid; D019833:Genistein; D020928:Mitogen-Activated Protein Kinases