4lmu
Crystal structure of Pim1 in complex with the inhibitor Quercetin (resulting from displacement of SKF86002)
Structural highlights
FunctionPIM1_HUMAN Proto-oncogene with serine/threonine kinase activity involved in cell survival and cell proliferation and thus providing a selective advantage in tumorigenesis. Exerts its oncogenic activity through: the regulation of MYC transcriptional activity, the regulation of cell cycle progression and by phosphorylation and inhibition of proapoptotic proteins (BAD, MAP3K5, FOXO3). Phosphorylation of MYC leads to an increase of MYC protein stability and thereby an increase of transcriptional activity. The stabilization of MYC exerted by PIM1 might explain partly the strong synergism between these two oncogenes in tumorigenesis. Mediates survival signaling through phosphorylation of BAD, which induces release of the anti-apoptotic protein Bcl-X(L)/BCL2L1. Phosphorylation of MAP3K5, an other proapoptotic protein, by PIM1, significantly decreases MAP3K5 kinase activity and inhibits MAP3K5-mediated phosphorylation of JNK and JNK/p38MAPK subsequently reducing caspase-3 activation and cell apoptosis. Stimulates cell cycle progression at the G1-S and G2-M transitions by phosphorylation of CDC25A and CDC25C. Phosphorylation of CDKN1A, a regulator of cell cycle progression at G1, results in the relocation of CDKN1A to the cytoplasm and enhanced CDKN1A protein stability. Promote cell cycle progression and tumorigenesis by down-regulating expression of a regulator of cell cycle progression, CDKN1B, at both transcriptional and post-translational levels. Phosphorylation of CDKN1B,induces 14-3-3-proteins binding, nuclear export and proteasome-dependent degradation. May affect the structure or silencing of chromatin by phosphorylating HP1 gamma/CBX3. Acts also as a regulator of homing and migration of bone marrow cells involving functional interaction with the CXCL12-CXCR4 signaling axis.[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedThe small kinase inhibitor SKF86002 lacks intrinsic fluorescence but becomes fluorescent upon binding to the ATP-binding sites of p38 mitogen-activated protein kinase (p38alpha). It was found that co-crystals of this compound with various kinases were distinguishable by their strong fluorescence. The co-crystals of SKF86002 with p38alpha, Pim1, ASK1, HCK and AMPK were fluorescent. Addition of SKF86002, which binds to the ATP site, to the co-crystallization solution of HCK promoted protein stability and thus facilitated the production of crystals that otherwise would not grow in the apo form. It was further demonstrated that the fluorescence of SKF86002 co-crystals can be applied to screen for candidate kinase inhibitors. When a compound binds competitively to the ATP-binding site of a kinase crystallized with SKF86002, it displaces the fluorescent SKF86002 and the crystal loses its fluorescence. Lower fluorescent signals were reported after soaking SKF86002-Pim1 and SKF86002-HCK co-crystals with the inhibitors quercetin, a quinazoline derivative and A-419259. Determination of the SKF86002-Pim1 and SKF86002-HCK co-crystal structures confirmed that SKF86002 interacts with the ATP-binding sites of Pim1 and HCK. The structures of Pim1-SKF86002 crystals soaked with the inhibitors quercetin and a quinazoline derivative and of HCK-SKF86002 crystals soaked with A-419259 were determined. These structures were virtually identical to the deposited crystal structures of the same complexes. A KINOMEscan assay revealed that SKF86002 binds a wide variety of kinases. Thus, for a broad range of kinases, SKF86002 is useful as a crystal marker, a crystal stabilizer and a marker to identify ligand co-crystals for structural analysis. Kinase crystal identification and ATP-competitive inhibitor screening using the fluorescent ligand SKF86002.,Parker LJ, Taruya S, Tsuganezawa K, Ogawa N, Mikuni J, Honda K, Tomabechi Y, Handa N, Shirouzu M, Yokoyama S, Tanaka A Acta Crystallogr D Biol Crystallogr. 2014 Feb;70(Pt 2):392-404. doi:, 10.1107/S1399004713028654. Epub 2014 Jan 29. PMID:24531473[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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