Serine/threonine kinase which is involved in the regulation of apoptosis, autophagy, transcription, translation and actin cytoskeleton reorganization. Involved in the regulation of smooth muscle contraction. Regulates both type I (caspase-dependent) apoptotic and type II (caspase-independent) autophagic cell deaths signal, depending on the cellular setting. Involved in regulation of starvation-induced autophagy. Regulates myosin phosphorylation in both smooth muscle and non-muscle cells. In smooth muscle, regulates myosin either directly by phosphorylating MYL12B and MYL9 or through inhibition of smooth muscle myosin phosphatase (SMPP1M) via phosphorylation of PPP1R12A; the inhibition of SMPP1M functions to enhance muscle responsiveness to Ca(2+) and promote a contractile state. Phosphorylates MYL12B in non-muscle cells leading to reorganization of actin cytoskeleton. Isoform 2 can phosphorylate myosin, PPP1R12A and MYL12B. Overexpression leads to condensation of actin stress fibers into thick bundles. Involved in actin filament focal adhesion dynamics. The function in both reorganization of actin cytoskeleton and focal adhesion dissolution is modulated by RhoD. Positively regulates canonical Wnt/beta-catenin signaling through interaction with NLK and TCF7L2. Phosphorylates RPL13A on 'Ser-77' upon interferon-gamma activation which is causing RPL13A release from the ribosome, RPL13A association with the GAIT complex and its subsequent involvement in transcript-selective translation inhibition. Enhances transcription from AR-responsive promoters in a hormone- and kinase-dependent manner. Involved in regulation of cell cycle progression and cell proliferation. May be a tumor suppressor. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] A sequential activation is proposed: autophosphorylation at consensus sites is leading to dimerization of the catalytic domain stabilized by phosphorylation at Ser-50 and activation segment exchange (producing an active confirmation of both kinase modules in trans) followed by phosphorylation at Thr-180 in the activation segment and at other regulatory sites (Probable). Phosphorylation at Thr-180, Thr-225 and Thr-265 is essential for activity. Oligomerization is required for full enzymatic activity. Inhibited by pyridone-6 (K00225), a potent, ATP-competitive inhibitor. Homooligomer in its kinase-active form (homotrimers and homodimers are reported); monomeric in its kinase-inactive form. Homodimerization is required for activation segment autophosphorylation (Probable). Isoform 1 and isoform 2 interact with myosin and PPP1R12A; interaction of isoform 1 with PPP1R12A is inhibited by RhoA dominant negative form. Interacts with NLK, DAXX, STAT3, RHOD (GTP-bound form) and TCP10L. Interacts with PAWR; the interaction is reported conflictingly: according to PubMed:17953487 does not interact with PAWR. Interacts with ULK1; may be a substrate of ULK1. Predominantly localizes to the cytoplasm but can shuttle between the nucleus and cytoplasm; cytoplasmic localization is promoted by phosphorylation at Thr-299 and involves Rho/Rock signaling. Widely expressed. Isoform 1 and isoform 2 are expressed in the bladder smooth muscle. The phosphorylation status is critical for kinase activity, oligomerization and intracellular localization. Phosphorylation at Thr-180, Thr-225 and Thr-265 is essential for activity. The phosphorylated form is localized in the cytoplasm promoted by phosphorylation at Thr-299; nuclear translocation or retention is maximal when it is not phosphorylated. Phosphorylation increases the trimeric form, and its dephosphorylation favors a kinase-inactive monomeric form. Both isoform 1 and isoform 2 can undergo autophosphorylation. The internal splice site between exon 8 and the 3' UTR, which yields this truncated isoform, is non-canonical. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. DAP kinase subfamily.