Lassar, Andrew2010-12-082009Lassar, Andrew B. 2009. The p38 MAPK family, a pushmi-pullyu of skeletal muscle differentiation. The Journal of Cell Biology 187(7): 941-943.0021-9525http://nrs.harvard.edu/urn-3:HUL.InstRepos:4621009In this issue, Gillespie et al. (Gillespie et al. 2009. J. Cell Biol. doi:10.1083/jcb.200907037) demonstrate that the mitogen-activated protein kinase isoform p38-γ plays a crucial role in blocking the premature differentiation of satellite cells, a skeletal muscle stem cell population. p38-γ puts the brakes on skeletal muscle differentiation by promoting the association of the transcription factor MyoD with the histone methyltransferase, KMT1A, which act together in a complex to repress the premature expression of the gene encoding the myogenic transcription factor Myogenin.en-USJournal Article2010-12-0810.1083/jcb.200911123