The p38α/β MAPK Functions as a Molecular Switch to Activate the Quiescent Satellite Cell

• Published in: The Journal of cell biology Vol. 169; no. 1; pp. 105 - 116
• Main Authors: Jones, Nathan C., Tyner, Kristina J., Nibarger, Lisa, Stanley, Heather M., Dawn D. W. Cornelison, Fedorov, Yuri V., Olwin, Bradley B.
• Format: Journal Article
• Language: English
• Published: Rockefeller University Press 11.04.2005; The Rockefeller University Press
• Subjects: Antibodies; Artificial satellites; Cell culture techniques; Cell cycle; Cell growth; Cell lines; Cell nucleus; Cellular differentiation; Cultured cells; Skeletal muscle satellite cells
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200408066

Somatic stem cells cycle slowly or remain quiescent until required for tissue repair and maintenance. Upon muscle injury, stem cells that lie between the muscle fiber and basal lamina (satellite cells) are activated, proliferate, and eventually differentiate to repair the damaged muscle. Satellite cells in healthy muscle are quiescent, do not express MyoD family transcription factors or cell cycle regulatory genes and are insulated from the surrounding environment. Here, we report that the p38α/β family of mitogen-activated protein kinases (MAPKs) reversibly regulates the quiescent state of the skeletal muscle satellite cell. Inhibition of p38α/β MAPKs (a) promotes exit from the cell cycle, (b) prevents differentiation, and (c) insulates the cell from most external stimuli allowing the satellite cell to maintain a quiescent state. Activation of satellite cells and p38α/β MAPKs occurs concomitantly, providing further support that these MAPKs function as a molecular switch for satellite cell activation.