%0 Journal Article
%T Full-length αIIbβ3 cryo-EM structure reveals intact integrin initiate-activation intrinsic architecture.
%A Huo T
%A Wu H
%A Moussa Z
%A Sen M
%A Dalton V
%A Wang Z
%J Structure
%V 32
%N 7
%D 2024 Jul 11
%M 38579706
%F 5.871
%R 10.1016/j.str.2024.03.006
%X Integrin αIIbβ3 is the key receptor regulating platelet retraction and accumulation and a proven drug-target for antithrombotic therapies. Here we resolve the cryo-EM structures of the full-length αIIbβ3, which covers three distinct states along the activation pathway. Firstly, we obtain the αIIbβ3 structure at 3 Å resolution in the inactive state, revealing the overall topology of the heterodimer with the transmembrane (TM) helices and the ligand-binding domain tucked in a specific angle proximity to the TM region. After the addition of a Mn2+ agonist, we resolve two coexisting structures representing two new states between inactive and active state. Our structures show conformational changes of the αIIbβ3 activating trajectory and a unique twisting of the integrin legs, which is required for platelets accumulation. Our structure provides direct structural evidence for how the lower legs are involved in full-length integrin activation mechanisms and offers a new strategy to target the αIIbβ3 lower leg.