1nys
From Proteopedia
Crystal Structure of Activin A Bound to the ECD of ActRIIB P41
Structural highlights
Function[AVR2A_RAT] 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 A, activin B and inhibin A. [INHBA_HUMAN] Inhibins and activins inhibit and activate, respectively, the secretion of follitropin by the pituitary gland. Inhibins/activins are involved in regulating a number of diverse functions such as hypothalamic and pituitary hormone secretion, gonadal hormone secretion, germ cell development and maturation, erythroid differentiation, insulin secretion, nerve cell survival, embryonic axial development or bone growth, depending on their subunit composition. Inhibins appear to oppose the functions of activins. 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 PubMedThe TGF-beta superfamily of ligands and receptors stimulate cellular events in diverse processes ranging from cell fate specification in development to immune suppression. Activins define a major subgroup of TGF-beta ligands that regulate cellular differentiation, proliferation, activation and apoptosis. Activins signal through complexes formed with type I and type II serine/threonine kinase receptors. We have solved the crystal structure of activin A bound to the extracellular domain of a type II receptor, ActRIIB, revealing the details of this interaction. ActRIIB binds to the outer edges of the activin finger regions, with the two receptors juxtaposed in close proximity, in a mode that differs from TGF-beta3 binding to type II receptors. The dimeric activin A structure differs from other known TGF-beta ligand structures, adopting a compact folded-back conformation. The crystal structure of the complex is consistent with recruitment of two type I receptors into a close packed arrangement at the cell surface and suggests that diversity in the conformational arrangements of TGF-beta ligand dimers could influence cellular signaling processes. Structures of an ActRIIB:activin A complex reveal a novel binding mode for TGF-beta ligand:receptor interactions.,Thompson TB, Woodruff TK, Jardetzky TS EMBO J. 2003 Apr 1;22(7):1555-66. PMID:12660162[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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