Catalytic activity:ATP + a protein = ADP + a phosphoprotein. ,cofactor:Magnesium. ,enzyme regulation:Activated by phosphorylation by PKN1 and autophosphorylation on Thr-161 and Ser-165. ,Function:Stress-activated component of a protein kinase signal transduction cascade. Regulates the JNK and p38 pathways. Pro-apoptotic. Role in regulation of S and G2 cell cycle checkpoint by direct phosphorylation of CHEK2. Isoform 1 , but not isoform 2 , causes cell shrinkage and disruption of actin stress fibers. Isoform 1 may have role in neoplastic cell transformation and cancer development. Isoform 1 , but not isoform 2 , phosphorylates histone H3 at 'Ser-28'. ,similarity:Belongs to the protein kinase superfamily. STE Ser/Thr protein kinase family. MAP kinase kinase kinase subfamily. ,similarity:Contains 1 protein kinase domain. ,similarity:Contains 1 SAM (sterile alpha motif) domain. ,subcellular location:Translocates to the nucleus upon ultraviolet B irradiation. ,subunit:Homodimer. Interacts with PKN1 and ZNF33A. ,tissue specificity:Ubiquitously expressed. Isoform 2 is the predominant form in all tissues examined , except for liver , in which isoform 1 is more highly expressed. ,
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