Protein kinase A sixfold mutant model of Aurora B with inhibitor VX-680
[KAPCA_HUMAN] Phosphorylates a large number of substrates in the cytoplasm and the nucleus. Regulates the abundance of compartmentalized pools of its regulatory subunits through phosphorylation of PJA2 which binds and ubiquitinates these subunits, leading to their subsequent proteolysis. Phosphorylates CDC25B, ABL1, NFKB1, CLDN3, PSMC5/RPT6, PJA2, RYR2, RORA, TRPC1 and VASP. RORA is activated by phosphorylation. Required for glucose-mediated adipogenic differentiation increase and osteogenic differentiation inhibition from osteoblasts. Involved in the regulation of platelets in response to thrombin and collagen; maintains circulating platelets in a resting state by phosphorylating proteins in numerous platelet inhibitory pathways when in complex with NF-kappa-B (NFKB1 and NFKB2) and I-kappa-B-alpha (NFKBIA), but thrombin and collagen disrupt these complexes and free active PRKACA stimulates platelets and leads to platelet aggregation by phosphorylating VASP. Prevents the antiproliferative and anti-invasive effects of alpha-difluoromethylornithine in breast cancer cells when activated. RYR2 channel activity is potentiated by phosphorylation in presence of luminal Ca(2+), leading to reduced amplitude and increased frequency of store overload-induced Ca(2+) release (SOICR) characterized by an increased rate of Ca(2+) release and propagation velocity of spontaneous Ca(2+) waves, despite reduced wave amplitude and resting cytosolic Ca(2+). TRPC1 activation by phosphorylation promotes Ca(2+) influx, essential for the increase in permeability induced by thrombin in confluent endothelial monolayers. PSMC5/RPT6 activation by phosphorylation stimulates proteasome. Regulates negatively tight junction (TJs) in ovarian cancer cells via CLDN3 phosphorylation. NFKB1 phosphorylation promotes NF-kappa-B p50-p50 DNA binding. Involved in embryonic development by down-regulating the Hedgehog (Hh) signaling pathway that determines embryo pattern formation and morphogenesis. Isoform 2 phosphorylates and activates ABL1 in sperm flagellum to promote spermatozoa capacitation. Prevents meiosis resumption in prophase-arrested oocytes via CDC25B inactivation by phosphorylation. May also regulate rapid eye movement (REM) sleep in the pedunculopontine tegmental (PPT). Phosphorylates APOBEC3G and AICDA.           [IPKA_HUMAN] Extremely potent competitive inhibitor of cAMP-dependent protein kinase activity, this protein interacts with the catalytic subunit of the enzyme after the cAMP-induced dissociation of its regulatory chains.
Publication Abstract from PubMed
We describe here mutations of the catalytic subunit alpha of protein kinase A (PKA) that introduce amino acid side chains into the ATP binding site and progressively transform the pocket to mimic that of Aurora protein kinases. The resultant PKA variants are enzymatically active and exhibit high affinity for ATP site inhibitors that are specific for Aurora kinases. These features make the Aurora-chimeric PKA a valuable tool for structure based drug discovery tasks. Analysis of crystal structures of the chimera reveal the roles of individual amino acid residues in the binding of a variety of inhibitors, offering key insights into selectivity mechanisms. Furthermore the high affinity for Aurora kinase specific inhibitors, combined with the favorable crystallizability properties of PKA allow rapid determination of inhibitor complex structures at atomic resolution. We demonstrate the utility of the Aurora-chimeric PKA by measuring binding kinetics for three Aurora kinase specific inhibitors, and present the X ray structures of the chimeric enzyme in complex with VX 680 (MK 0457) and JNJ 7706621 (Aurora kinase/Cdk inhibitor).
Mutants of protein kinase A that mimic the ATP-binding site of Aurora kinase.,Pflug A, de Oliveira TM, Bossemeyer D, Engh RA Biochem J. 2011 Jul 21. PMID:21774789
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.