Serine/Threonine Kinase 25 (STK25)

The SOK1 protein is 426 amino acids long and has a predicted molecular weight of approximately 48 kD. SOK1 is activated 2-fold by autophosphorylation and 3- to 7-fold by reactive oxygen intermediates, but is not activated by growth factors, alkylating agents, cytokines, or environmental stresses such as heat shock or osmolar stress. The SOK1 protein localized to the cytoplasm in NIH 3T3 fibroblasts.The predicted YSK1 protein contains an N-terminal kinase domain and lacks a putative Cdc42/Rac1-binding domain. Although the deduced kinase domain of YSK1 shows approximately 40% sequence identity to the kinase domains of yeast MAPKKKs, it is more similar to the kinase domains of Ste20-related kinases such as yeast Sps1, and human MST1 and GCK.