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Dimerization/Docking domain of Cyclic GMP-dependent Protein Kinase I Cyclic GMP-dependent Protein Kinase I (PKG1 or cGKI) is a Serine/Threonine Kinase (STK), catalyzing the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. cGKI exists as two splice variants, cGKI-alpha and cGKI-beta. They contain an N-terminal regulatory domain containing a dimerization/docking region and an autoinhibitory pseudosubstrate region, two cGMP-binding domains, and a C-terminal catalytic domain. Binding of cGMP to both binding sites releases the inhibition of the catalytic center by the pseudosubstrate region, allowing autophosphorylation and activation of the kinase. cGKI is a soluble protein expressed in all smooth muscles, platelets, cerebellum, and kidney. It is also expressed at lower concentrations in other tissues. It is involved in the regulation of smooth muscle tone, smooth cell proliferation, and platelet activation. The dimerization/docking (D/D) domain is a leucine/isoleucine zipper that mediates both homodimerization and interaction with isotype-specific G-kinase-anchoring proteins (GKAPs). The D/D domain of the two variants (alpha and beta) differ, allowing their targeting to different subcellular compartments and intracellular substrates. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",