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Catalytic domain of the Serine/Threonine Kinases, MAP/microtubule affinity-regulating kinases STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. MARKs, also called Partitioning-defective 1 (Par1) proteins, function as regulators of diverse cellular processes in nematodes, Drosophila, yeast, and vertebrates. They are involved in embryogenesis, epithelial cell polarization, cell signaling, and neuronal differentiation. MARKs phosphorylate tau and related microtubule-associated proteins (MAPs), and regulates microtubule-based intracellular transport. Vertebrates contain four isoforms, namely MARK1 (or Par1c), MARK2 (or Par1b), MARK3 (Par1a), and MARK4 (or MARKL1). Known substrates of MARKs include the cell cycle-regulating phosphatase Cdc25, tyrosine phosphatase PTPH1, MAPK scaffolding protein KSR1, class IIa histone deacetylases, and plakophilin 2. The MARK subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",