5i0b
From Proteopedia
Structure of PAK4
Structural highlights
Function[PAK4_HUMAN] Serine/threonine protein kinase that plays a role in a variety of different signaling pathways including cytoskeleton regulation, cell migration, growth, proliferation or cell survival. Activation by various effectors including growth factor receptors or active CDC42 and RAC1 results in a conformational change and a subsequent autophosphorylation on several serine and/or threonine residues. Phosphorylates and inactivates the protein phosphatase SSH1, leading to increased inhibitory phosphorylation of the actin binding/depolymerizing factor cofilin. Decreased cofilin activity may lead to stabilization of actin filaments. Phosphorylates LIMK1, a kinase that also inhibits the activity of cofilin. Phosphorylates integrin beta5/ITGB5 and thus regulates cell motility. Phosphorylates ARHGEF2 and activates the downstream target RHOA that plays a role in the regulation of assembly of focal adhesions and actin stress fibers. Stimulates cell survival by phosphorylating the BCL2 antagonist of cell death BAD. Alternatively, inhibits apoptosis by preventing caspase-8 binding to death domain receptors in a kinase independent manner. Plays a role in cell-cycle progression by controlling levels of the cell-cycle regulatory protein CDKN1A and by phosphorylating RAN.[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedp21-Activated kinases (PAKs) which belong to the family of ste20 serine/threonine protein kinases regulate cytoskeletal reorganization, cell motility, cell proliferation, and oncogenic transformation which are all related to the cellular functions during cancer induction and metastasis. The fact that PAK mutations are detected in multiple tumor tissues makes PAKs a novel therapeutic drug target. In this study, an imidazo[4,5-b]pyridine-based PAK4 inhibitor, KY-04045 (6-Bromo-2-(3-isopropyl-1-methyl-1H-pyrazol-4-yl)-1H-imidazo[4,5-b]pyridine), was discovered using a virtual site-directed fragment-based drug design and was validated using an inhibition assay. Although PAK4 affinity to KY-04045 seems much weaker than that of the reported PAK4 inhibitors, the location of KY-04045 is clearly defined in the structure of PAK4 co-crystallized with KY-04045. The crystal structure illustrates that the pyrazole and imidazopyridine rings of KY-04045 are sufficient for mediating PAK4 hinge loop interaction. Hence, we believe that KY-04045 can be exploited as a basic building block in designing novel imidazo[4,5-b]pyridine-based PAK4 inhibitors. The discovery and the structural basis of an imidazo[4,5-b]pyridine-based p21-activated kinase 4 inhibitor.,Park JK, Kim S, Han YJ, Kim SH, Kang NS, Lee H, Park S Bioorg Med Chem Lett. 2016 Jun 1;26(11):2580-3. doi: 10.1016/j.bmcl.2016.04.037. , Epub 2016 Apr 16. PMID:27117431[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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