3vc4 | pdb_00003vc4
Exploitation of hydrogen bonding constraints and flat hydrophobic energy landscapes in Pim-1 kinase needle screening and inhibitor design
Structural highlights
Function[PIM1_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 PubMedWe have studied the subtleties of fragment docking and binding using data generated in a Pim-1 kinase inhibitor program. Crystallographic and docking data analyses have been undertaken using inhibitor complexes derived from an in-house surface plasmon resonance (SPR) fragment screen, a virtual needle screen, and a de novo designed fragment inhibitor hybrid. These investigations highlight that fragments that do not fill their binding pocket can exhibit promiscuous hydrophobic interactions due to the lack of steric constraints imposed on them by the boundaries of said pocket. As a result, docking modes that disagree with an observed crystal structure but maintain key crystallographically observed hydrogen bonds still have potential value in ligand design and optimization. This observation runs counter to the lore in fragment-based drug design that all fragment elaboration must be based on the parent crystal structure alone. Implications of Promiscuous Pim-1 Kinase Fragment Inhibitor Hydrophobic Interactions for Fragment-Based Drug Design.,Good AC, Liu J, Hirth B, Asmussen G, Xiang Y, Biemann HP, Bishop KA, Fremgen T, Fitzgerald M, Gladysheva T, Jain A, Jancsics K, Metz M, Papoulis A, Skerlj R, Stepp JD, Wei RR J Med Chem. 2012 Mar 5. PMID:22339127[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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