Chemical cross‐linking leads to two high molecular mass aggregates of rat α 1 β 1 integrin differing in their conformation but not in their composition

FEBS Letters

Hofmann, Werner¹  Löster, Klemens¹  Baum, Oliver¹  Reutter, Werner¹ 

[1] Institut für Molekularbiologie und Biochemie, Freie Universität Berlin, Arnimallee 22, D-14195 Berlin-Dahlem, Germany

关键词: Chemical cross-linking;    Rat α 1 β 1 integrin;    DSS;    disuccinimidylsuberate;    DSP;    dithiobis(succinimidylpropionate);    DTT;    dithiothreitol;    mAb;    monoclonal antibody;    M r;    relative molecular mass;   

DOI  :  10.1016/0014-5793(95)01053-H

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In order to detect protein interactions of the collagen/laminin receptor α ₁ β ₁ integrin, covalent chemical cross-linking was performed with the homo-bifunctional, amine reactive reagents DSS (disuccinimidylsuberate) and DSP (dithiobis(succinimidylpropionate)). After cross-linking of the 190 kDa rat α ₁ integrin subunit, immunoblotting revealed two additional, immunoreactive, high molecular mass complexes (M _r 240/290 k). Generation of the 240/290 kDa aggregates depended on the presence of the intact tertiary protein structure. As shown with immunoaffinity purified proteins, the 240/290 kDa aggregates consist exclusively of α ₁ and β ₁ integrin subunits. No other cross-linked proteins associated with the α ₁ or β ₁ subunit were detected. In contrast to the non-cross-linkable α ₁ β ₁ integrin, the 240/290 kDa aggregates presumably represent active forms of the adhesion receptor, because both bound in vitro to collagen I and IV. This ability of α ₁ β ₁ integrin to cross-link and produce two additional high molecular mass forms is shared by rat α ₉ β ₁ integrin. Thus, the cross-linking approach directly indicates that β ₁ integrins occur in different conformations caused by variations in the folding and/or spatial arrangement of their subunits.

【 授权许可】

Unknown