serinethreoninekinaasit

Serine/threonine kinases, in Finnish serinethreoninekinaasit, constitute a broad family of protein kinases that catalyze the transfer of a phosphate group from ATP to the hydroxyl group of serine or threonine residues in substrate proteins. This phosphorylation is a key mechanism for regulating enzyme activity, protein-protein interactions, subcellular localization, and stability, and it influences pathways governing metabolism, growth, differentiation, and apoptosis.

Most enzymes in this group share a conserved catalytic domain of roughly 250–300 amino acids with motifs such as the VAIK motif, the HRD motif, and the DFG motif. Activation and regulation occur through various mechanisms, including phosphorylation within the activation loop, binding of calcium/calmodulin, cyclic nucleotides, or lipid signals, and through interactions with regulatory subunits or scaffold proteins.

Classification includes several major families, such as the AGC group (protein kinases A, G, C), CAMK group (calcium/calmodulin-dependent kinases), CMGC group (CDKs, MAPKs, GSKs, CLK), CK1, CK2, STE kinases, among others. Well-known examples are PKA, PKB/AKT, AMPK, and various cyclin-dependent kinases; these enzymes influence numerous cellular processes and are common targets of pharmacological inhibitors.

Clinical and research relevance: dysregulation of serine/threonine kinases is linked to cancer, metabolic disorders, neurodegenerative diseases; inhibitors are used in cancer therapy and research. They operate largely in parallel with tyrosine kinases, which phosphorylate tyrosine residues, though cross-talk exists in signaling networks.