3q4u
Crystal structure of the ACVR1 kinase domain in complex with LDN-193189
Structural highlights
DiseaseACVR1_HUMAN Fibrodysplasia ossificans progressiva. Defects in ACVR1 are a cause of fibrodysplasia ossificans progressiva (FOP) [MIM:135100. FOP is a rare autosomal dominant disorder of skeletal malformations and progressive extraskeletal ossification. Heterotopic ossification in FOP begins in childhood and can be induced by trauma or may occur without warning. Bone formation is episodic and progressive, leading to extra-articular ankylosis of all major joints of the axial and appendicular skeleton, rendering movement impossible.[1] [2] [3] FunctionACVR1_HUMAN On ligand binding, forms a receptor complex consisting of two type II and two type I transmembrane serine/threonine kinases. Type II receptors phosphorylate and activate type I receptors which autophosphorylate, then bind and activate SMAD transcriptional regulators. Receptor for activin. May be involved for left-right pattern formation during embryogenesis (By similarity). Publication Abstract from PubMedGrowth factor signaling pathways are tightly regulated by phosphorylation and include many important kinase targets of interest for drug discovery. Small molecule inhibitors of the bone morphogenetic protein (BMP) receptor kinase ALK2 (ACVR1) are needed urgently to treat the progressively debilitating musculoskeletal disease fibrodysplasia ossificans progressiva (FOP). Dorsomorphin analogues, first identified in zebrafish, remain the only BMP inhibitor chemotype reported to date. By screening an assay panel of 250 recombinant human kinases we identified a highly selective 2-aminopyridine-based inhibitor K02288 with in vitro activity against ALK2 at low nanomolar concentrations similar to the current lead compound LDN-193189. K02288 specifically inhibited the BMP-induced Smad pathway without affecting TGF-beta signaling and induced dorsalization of zebrafish embryos. Comparison of the crystal structures of ALK2 with K02288 and LDN-193189 revealed additional contacts in the K02288 complex affording improved shape complementarity and identified the exposed phenol group for further optimization of pharmacokinetics. The discovery of a new chemical series provides an independent pharmacological tool to investigate BMP signaling and offers multiple opportunities for pre-clinical development. A new class of small molecule inhibitor of BMP signaling.,Sanvitale CE, Kerr G, Chaikuad A, Ramel MC, Mohedas AH, Reichert S, Wang Y, Triffitt JT, Cuny GD, Yu PB, Hill CS, Bullock AN PLoS One. 2013 Apr 30;8(4):e62721. doi: 10.1371/journal.pone.0062721. Print 2013. PMID:23646137[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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