In response to muscle injury, satellite cells activate the p38 alpha/beta MAPK pathway to exit quiescence, then proliferate, fix skeletal muscle, and till self-renew, replenishing the quiescent satellite cell pool. Although satellite cells are capable of asymmetric division, the mechanisms regulating satellite cell self-renewal are usually not understood. We observed that satellite cells, as soon as activated, enter the cell cycle plus a subset undergoes asymmetric division, Molecular mass renewing the satellite cell pool. Asymmetric localization on the Par complicated activates p38 alpha/beta MAPK in just one daughter cell, inducing MyoD, which permits cell cycle entry and generates a proliferating myoblast. The absence of p38 alpha/beta MAPK signaling inside the other daughter cell prevents MyoD induction, renewing the quiescent satellite cell. Therefore, satellite cells use a mechanism AGK2 to make distinct daughter cells, coupling the Par complex and p38 alpha/beta MAPK signaling to link the response to muscle injury with satellite cell self-renewal.