1gmi
Structure of the c2 domain from novel protein kinase C epsilon
Structural highlights
FunctionKPCE_RAT Calcium-independent, phospholipid- and diacylglycerol (DAG)-dependent serine/threonine-protein kinase that plays essential roles in the regulation of multiple cellular processes linked to cytoskeletal proteins, such as cell adhesion, motility, migration and cell cycle, functions in neuron growth and ion channel regulation, and is involved in immune response, cancer cell invasion and regulation of apoptosis. Mediates cell adhesion to the extracellular matrix via integrin-dependent signaling, by mediating angiotensin-2-induced activation of integrin beta-1 (ITGB1) in cardiac fibroblasts. Phosphorylates MARCKS, which phosphorylates and activates PTK2/FAK, leading to the spread of cardiomyocytes. Involved in the control of the directional transport of ITGB1 in mesenchymal cells by phosphorylating vimentin (VIM), an intermediate filament (IF) protein. In epithelial cells, associates with and phosphorylates keratin-8 (KRT8), which induces targeting of desmoplakin at desmosomes and regulates cell-cell contact. Phosphorylates IQGAP1, which binds to CDC42, mediating epithelial cell-cell detachment prior to migration. During cytokinesis, forms a complex with YWHAB, which is crucial for daughter cell separation, and facilitates abscission by a mechanism which may implicate the regulation of RHOA. In cardiac myocytes, regulates myofilament function and excitation coupling at the Z-lines, where it is indirectly associated with F-actin via interaction with COPB1. During endothelin-induced cardiomyocyte hypertrophy, mediates activation of PTK2/FAK, which is critical for cardiomyocyte survival and regulation of sarcomere length. Plays a role in the pathogenesis of dilated cardiomyopathy via persistent phosphorylation of troponin I (TNNI3). Involved in nerve growth factor (NFG)-induced neurite outgrowth and neuron morphological change independently of its kinase activity, by inhibition of RHOA pathway, activation of CDC42 and cytoskeletal rearrangement. May be involved in presynaptic facilitation by mediating phorbol ester-induced synaptic potentiation. Phosphorylates gamma-aminobutyric acid receptor subunit gamma-2 (GABRG2), which reduces the response of GABA receptors to ethanol and benzodiazepines and may mediate acute tolerance to the intoxicating effects of ethanol. Upon PMA treatment, phosphorylates the capsaicin- and heat-activated cation channel TRPV1, which is required for bradykinin-induced sensitization of the heat response in nociceptive neurons. Is able to form a complex with PDLIM5 and N-type calcium channel, and may enhance channel activities and potentiates fast synaptic transmission by phosphorylating the pore-forming alpha subunit CACNA1B (CaV2.2). Downstream of TLR4, plays an important role in the lipopolysaccharide (LPS)-induced immune response by phosphorylating and activating TICAM2/TRAM, which in turn activates the transcription factor IRF3 and subsequent cytokines production. In differentiating erythroid progenitors, is regulated by EPO and controls the protection against the TNFSF10/TRAIL-mediated apoptosis, via BCL2. May be involved in the regulation of the insulin-induced phosphorylation and activation of AKT1.[1] [2] [3] 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 PubMedProtein kinase Cepsilon (PKCepsilon) is a member of the novel PKCs which are activated by acidic phospholipids, diacylglycerol and phorbol esters, but lack the calcium dependence of classical PKC isotypes. The crystal structures of the C2 domain of PKCepsilon, crystallized both in the absence and in the presence of the two acidic phospholipids, 1,2-dicaproyl-sn-phosphatidyl-l-serine (DCPS) and 1,2-dicaproyl-sn-phosphatidic acid (DCPA), have now been determined at 2.1, 1.7 and 2.8 A resolution, respectively. The central feature of the PKCepsilon-C2 domain structure is an eight-stranded, antiparallel, beta-sandwich with a type II topology similar to that of the C2 domains from phospholipase C and from novel PKCdelta. Despite the similar topology, important differences are found between the structures of C2 domains from PKCs delta and epsilon, suggesting they be considered as different PKC subclasses. Site-directed mutagenesis experiments and structural changes in the PKCepsilon-C2 domain from crystals with DCPS or DCPA indicate, though phospholipids were not visible in these structures, that loops joining strands beta1-beta2 and beta5-beta6 participate in the binding to anionic membranes. The different behavior in membrane-binding and activation between PKCepsilon and classical PKCs appears to originate in localized structural changes, which include a major reorganization of the region corresponding to the calcium binding pocket in classical PKCs. A mechanism is proposed for the interaction of the PKCepsilon-C2 domain with model membranes that retains basic features of the docking of C2 domains from classical, calcium-dependent, PKCs. Structure of the C2 domain from novel protein kinase Cepsilon. A membrane binding model for Ca(2+)-independent C2 domains.,Ochoa WF, Garcia-Garcia J, Fita I, Corbalan-Garcia S, Verdaguer N, Gomez-Fernandez JC J Mol Biol. 2001 Aug 24;311(4):837-49. PMID:11518534[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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