MSK1 is a mitogen and stress activated protein kinase 1 which belongs to the AGC family of kinases and is related in structure to the ribosomal p70 S6 kinase subfamily. MSK1 can be activated by ERK1/2 and SAPK2/p38 MAP kinase. It is also known to be required for the phosphorylation of CREB, ATF1 H3 and HMG14 in response to mitogen and stress. Similar to RSK, MSK1 contains two kinase domains (N term and a C term). Once phosphorylated on Thr581 and Ser360 by ERK1/2 and SAPK2/p38, MSK1 aut