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Structure of catalytic domain of human protein kinase C beta II complexed with a bisindolylmaleimide inhibitor
Structural highlights
FunctionKPCB_HUMAN Calcium-activated, phospholipid- and diacylglycerol (DAG)-dependent serine/threonine-protein kinase involved in various cellular processes such as regulation of the B-cell receptor (BCR) signalosome, oxidative stress-induced apoptosis, androgen receptor-dependent transcription regulation, insulin signaling and endothelial cells proliferation. Plays a key role in B-cell activation by regulating BCR-induced NF-kappa-B activation. Mediates the activation of the canonical NF-kappa-B pathway (NFKB1) by direct phosphorylation of CARD11/CARMA1 at 'Ser-559', 'Ser-644' and 'Ser-652'. Phosphorylation induces CARD11/CARMA1 association with lipid rafts and recruitment of the BCL10-MALT1 complex as well as MAP3K7/TAK1, which then activates IKK complex, resulting in nuclear translocation and activation of NFKB1. Plays a direct role in the negative feedback regulation of the BCR signaling, by down-modulating BTK function via direct phosphorylation of BTK at 'Ser-180', which results in the alteration of BTK plasma membrane localization and in turn inhibition of BTK activity. Involved in apoptosis following oxidative damage: in case of oxidative conditions, specifically phosphorylates 'Ser-36' of isoform p66Shc of SHC1, leading to mitochondrial accumulation of p66Shc, where p66Shc acts as a reactive oxygen species producer. Acts as a coactivator of androgen receptor (ANDR)-dependent transcription, by being recruited to ANDR target genes and specifically mediating phosphorylation of 'Thr-6' of histone H3 (H3T6ph), a specific tag for epigenetic transcriptional activation that prevents demethylation of histone H3 'Lys-4' (H3K4me) by LSD1/KDM1A. In insulin signaling, may function downstream of IRS1 in muscle cells and mediate insulin-dependent DNA synthesis through the RAF1-MAPK/ERK signaling cascade. May participate in the regulation of glucose transport in adipocytes by negatively modulating the insulin-stimulated translocation of the glucose transporter SLC2A4/GLUT4. Under high glucose in pancreatic beta-cells, is probably involved in the inhibition of the insulin gene transcription, via regulation of MYC expression. In endothelial cells, activation of PRKCB induces increased phosphorylation of RB1, increased VEGFA-induced cell proliferation, and inhibits PI3K/AKT-dependent nitric oxide synthase (NOS3/eNOS) regulation by insulin, which causes endothelial dysfunction. Also involved in triglyceride homeostasis (By similarity).[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe conventional protein kinase C isoform, PKCII, is a signaling kinase activated during the hyperglycemic state and has been associated with the development of microvascular abnormalities associated with diabetes. PKCII, therefore, has been identified as a therapeutic target where inhibitors of its kinase activity are being pursued for treatment of microvascular-related diabetic complications. In this report, we describe the crystal structure of the catalytic domain of PKCbetaII complexed with an inhibitor at 2.6 A resolution. The kinase domain of PKCbetaII was cleaved and purified from full-length PKCbetaII expressed in baculovirus-infected insect cells. The overall kinase domain structure follows the classical bilobal fold and is in its fully activated conformation with three well-defined phosphorylated residues: Thr-500, Thr-641, and Ser-660. Different from the crystal structures of nonconventional PKC isoforms, the C-terminus of the PKCbetaII catalytic domain is almost fully ordered and features a novel alpha helix in the turn motif. An ATP-competitive inhibitor, 2-methyl-1H-indol-3-yl-BIM-1, was crystallized with the PKCbetaII catalytic domain as a dimer of two enzyme-inhibitor complexes. The bound inhibitor adopts a nonplanar conformation in the ATP-binding site, with the kinase domain taking on an intermediate, open conformation. This PKCbetaII-inhibitor complex represents the first structural description of any conventional PKC kinase domain. Given the pathogenic role of PKCbetaII in the development of diabetic complications, this structure can serve as a template for the rational design of inhibitors as potential therapeutic agents. Structure of the catalytic domain of human protein kinase C beta II complexed with a bisindolylmaleimide inhibitor.,Grodsky N, Li Y, Bouzida D, Love R, Jensen J, Nodes B, Nonomiya J, Grant S Biochemistry. 2006 Nov 28;45(47):13970-81. PMID:17115692[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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