Laminins are major cell-adhesive proteins consisting of α, β, and γ chains, in which the three C-terminal globular domains of the α chain (LMα/LG1-3) and the C-terminal tail region of the γ1 chain (LMγ1-tail) are required for binding to integrin. Despite the recent progress on the role of LMγ1-tail in coordinating the metal ion-dependent adhesion site of the integrin β subunit, the mechanism by which LMα/LG1-3 interacts with integrin remains to be elucidated. We found that basic residues on the bottom face of LMα5/LG2 are required for binding laminin-511 to α6β1 integrin. Intermolecular cysteine scanning assays demonstrated that the basic residues in LMα5/LG2 were in contact with the acidic residues within the laminin-binding X1 region of the integrin α subunit in the laminin-integrin complex. These results indicate that LMα5/LG2 interacts directly with the integrin α subunit and comprises a bipartite integrin binding site of laminin-511 with the LMγ1-tail.

中文翻译：

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层粘连蛋白-整合素相互作用的二分机制：层粘连蛋白α链的LG域中整合素结合位点的鉴定。

层粘连蛋白是主要的细胞粘附蛋白，由α，β和γ链组成，其中α链的三个C末端球状结构域（LMα/ LG1-3）和γ1链的C末端尾部区域（LMγ1 -tail）是与整联蛋白结合所必需的。尽管关于LMγ1-尾在协调整联蛋白β亚基的金属离子依赖性粘附位点中的作用方面有最新进展，但仍需阐明LMα/ LG1-3与整联蛋白相互作用的机理。我们发现，LMα5/ LG2底面上的碱性残基是将层粘连蛋白511与α6β1整联蛋白结合所必需的。分子间半胱氨酸扫描分析表明，LMα5/ LG2中的碱性残基与层粘连蛋白-整联蛋白复合物中整联蛋白α亚基的层粘连蛋白结合X1区域内的酸性残基接触。