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Catalytic domain of the Serine/Threonine Kinase, Death-Associated Protein Kinase 3 STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. DAPKs mediate cell death and act as tumor suppressors. They are necessary to induce cell death and their overexpression leads to death-associated changes including membrane blebbing, cell rounding, and formation of autophagic vesicles. Vertebrates contain three subfamily members with different domain architecture, localization, and function. DAPK3, also called DAP-like kinase (DLK) and zipper-interacting protein kinase (ZIPk), contains an N-terminal kinase domain and a C-terminal region with nuclear localization signals (NLS) and a leucine zipper motif that mediates homodimerization and interaction with other leucine zipper proteins. It interacts with Par-4, a protein that contains a death domain and interacts with actin filaments. DAPK3 is present in both the cytoplasm and nucleus. Its co-expression with Par-4 results in the co-localization of the two proteins to actin filaments. In addition to cell death, DAPK3 is also implicated in mediating cell motility and the contraction of smooth muscles. The DAPK3 subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.
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