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Relating conformation to function in integrin α5β1
DOI:10.1073/pnas.1605074113.png)
摘要
En 中文
Whether beta(1) integrin ectodomains visit conformational states similarly to beta(2) and beta(3) integrins has not been characterized. Furthermore, despite a wealth of activating and inhibitory antibodies to beta(1) integrins, the conformational states that these antibodies stabilize, and the relation of these conformations to function, remain incompletely characterized. Using negative-stain electron microscopy, we show that the integrin alpha(5)beta(1) ectodomain adopts extended-closed and extended-open conformations as well as a bent conformation. Antibodies SNAKA51, 8E3, N29, and 9EG7 bind to different domains in the alpha(5) or beta(1) legs, activate, and stabilize extended ectodomain conformations. Antibodies 12G10 and HUTS-4 bind to the beta(1) beta I domain and hybrid domains, respectively, activate, and stabilize the open headpiece conformation. Antibody TS2/16 binds a similar epitope as 12G10, activates, and appears to stabilize an open beta I domain conformation without requiring extension or hybrid domain swing-out. mAb13 and SG/19 bind to the beta I domain and beta I-hybrid domain interface, respectively, inhibit, and stabilize the closed conformation of the headpiece. The effects of the antibodies on cell adhesion to fibronectin substrates suggest that the extended-open conformation of alpha(5)beta(1) is adhesive and that the extended-closed and bent-closed conformations are nonadhesive. The functional effects and binding sites of antibodies and fibronectin were consistent with their ability in binding to alpha(5)beta(1) on cell surfaces to cross-enhance or inhibit one another by competitive or noncompetitive (allosteric) mechanisms.
Keyword:
X-RAY-SCATTERING
CRYSTAL-STRUCTURE
MONOCLONAL-ANTIBODIES
EXTRACELLULAR SEGMENT
FIBRONECTIN RECEPTOR
ELECTRON-MICROSCOPY
LEUKOCYTE INTEGRIN
REGULATORY REGION
LIGAND-BINDING
HYBRID DOMAIN
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期刊
P
IF:
9.1
论文数:
10.8W
被引数:
79.9W
机构
引用论文
Evaluation of the Chemical Reactions from Two Electrogenerated Species in Picoliter Volumes by Scanning Electrochemical Microscopy
ChemPhysChem
IF0
Regulation of integrin function:: evidence that bivalent-cation-induced conformational changes lead to the unmasking of ligand-binding sites within integrin α5β1
BIOCHEMICAL JOURNAL
IF4.3
Structure of a Complete Integrin Ectodomain in a Physiologic Resting State and Activation and Deactivation by Applied Forces
MOLECULAR CELL
IF16.6

