9e8a
From Proteopedia
(Difference between revisions)
| Line 1: | Line 1: | ||
| - | '''Unreleased structure''' | ||
| - | + | ==Integrin aIIbb3 bent conformation from human platelet membrane crude preparation== | |
| + | <StructureSection load='9e8a' size='340' side='right'caption='[[9e8a]], [[Resolution|resolution]] 2.75Å' scene=''> | ||
| + | == Structural highlights == | ||
| + | <table><tr><td colspan='2'>[[9e8a]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9E8A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9E8A FirstGlance]. <br> | ||
| + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.75Å</td></tr> | ||
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr> | ||
| + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=9e8a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9e8a OCA], [https://pdbe.org/9e8a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9e8a RCSB], [https://www.ebi.ac.uk/pdbsum/9e8a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9e8a ProSAT]</span></td></tr> | ||
| + | </table> | ||
| + | == Disease == | ||
| + | [https://www.uniprot.org/uniprot/ITA2B_HUMAN ITA2B_HUMAN] Defects in ITGA2B are a cause of Glanzmann thrombasthenia (GT) [MIM:[https://omim.org/entry/273800 273800]; also known as thrombasthenia of Glanzmann and Naegeli. GT is the most common inherited disease of platelets. It is an autosomal recessive disorder characterized by mucocutaneous bleeding of mild-to-moderate severity and the inability of this integrin to recognize macromolecular or synthetic peptide ligands. GT has been classified clinically into types I and II. In type I, platelets show absence of the glycoprotein IIb/beta-3 complexes at their surface and lack fibrinogen and clot retraction capability. In type II, the platelets express the glycoprotein IIb/beta-3 complex at reduced levels (5-20% controls), have detectable amounts of fibrinogen, and have low or moderate clot retraction capability. The platelets of GT 'variants' have normal or near normal (60-100%) expression of dysfunctional receptors.<ref>PMID:8282784</ref> <ref>PMID:7508443</ref> <ref>PMID:7706461</ref> <ref>PMID:8704171</ref> <ref>PMID:9215749</ref> <ref>PMID:9473221</ref> <ref>PMID:9763559</ref> <ref>PMID:9722314</ref> <ref>PMID:9734640</ref> <ref>PMID:9920835</ref> <ref>PMID:10607701</ref> <ref>PMID:11798398</ref> <ref>PMID:12181054</ref> <ref>PMID:12083483</ref> <ref>PMID:12424194</ref> <ref>PMID:12506038</ref> <ref>PMID:15099289</ref> <ref>PMID:15219201</ref> <ref>PMID:17018384</ref> | ||
| + | == Function == | ||
| + | [https://www.uniprot.org/uniprot/ITA2B_HUMAN ITA2B_HUMAN] Integrin alpha-IIb/beta-3 is a receptor for fibronectin, fibrinogen, plasminogen, prothrombin, thrombospondin and vitronectin. It recognizes the sequence R-G-D in a wide array of ligands. It recognizes the sequence H-H-L-G-G-G-A-K-Q-A-G-D-V in fibrinogen gamma chain. Following activation integrin alpha-IIb/beta-3 brings about platelet/platelet interaction through binding of soluble fibrinogen. This step leads to rapid platelet aggregation which physically plugs ruptured endothelial cell surface. | ||
| + | <div style="background-color:#fffaf0;"> | ||
| + | == Publication Abstract from PubMed == | ||
| + | Platelets fulfill their essential physiological roles sensing the extracellular environment through their membrane proteins. The native membrane environment provides essential regulatory cues that affect the protein structure and mechanism of action. Single-particle cryogenic electron microscopy (cryo-EM) has transformed structural biology by allowing high-resolution structures of membrane proteins to be solved from homogeneous samples. Our recent breakthroughs in data processing now make it feasible to obtain atomic-level-resolution protein structures from crude preparations in their native environments by integrating cryo-EM with the "build-and-retrieve" (BaR) data processing methodology. We applied this iterative bottom-up methodology on resting human platelet membranes for an in-depth systems biology approach to uncover how lipids, metal binding, post-translational modifications, and cofactor associations in the native environment regulate platelet function at the molecular level. Here, we report using cryo-EM followed by the BaR method to solve the unmodified integrin alphaIIbbeta3 structure directly from resting human platelet membranes in its inactivated and intermediate states at 2.75 and 2.67 A, respectively. Furthermore, we also solved a novel dimer conformation of alphaIIbbeta3 at 2.85 A formed by 2 intermediate states of alphaIIbbeta3. This may indicate a previously unknown self-regulatory mechanism of alphaIIbbeta3 in its native environment. In conclusion, our data show the power of using cryo-EM with the BaR method to determine 3 distinct structures including a novel dimer directly from natural sources. This approach allows us to identify unrecognized regulation mechanisms for proteins without artifacts owing to purification processes. These data have the potential to enrich our understanding of platelet signaling circuitry. | ||
| - | + | Elucidating the dynamics of integrin alphaIIbbeta3 from native platelet membranes by cryo-EM with build-and-retrieve method.,Han X, Zhang Z, Su CC, Lyu M, Miyagi M, Yu E, Nieman MT Blood Adv. 2025 Sep 23;9(18):4592-4606. doi: 10.1182/bloodadvances.2025016209. PMID:40472320<ref>PMID:40472320</ref> | |
| - | + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |
| - | [[Category: | + | </div> |
| + | <div class="pdbe-citations 9e8a" style="background-color:#fffaf0;"></div> | ||
| + | == References == | ||
| + | <references/> | ||
| + | __TOC__ | ||
| + | </StructureSection> | ||
| + | [[Category: Homo sapiens]] | ||
| + | [[Category: Large Structures]] | ||
| + | [[Category: Han X]] | ||
| + | [[Category: Nieman MT]] | ||
Current revision
Integrin aIIbb3 bent conformation from human platelet membrane crude preparation
| |||||||||||
