Structural basis for tetraspanin-dependent surface export and adhesive function of integrin α3β1
Integrin 3{beta}1 (ITG3{beta}1) is a member of an integrin subfamily that binds to laminin proteins and promotes attachment of epithelial cells to the basement membrane. ITG3{beta}1 forms a complex with the tetraspanin CD151, and loss-of-function mutations in both ITG3 and CD151 cause epidermolysis bullosa, a severe skin blistering disease resulting from a defect in basement membrane attachment.…
Integrin alpha3beta1 (ITG3beta1) is a vital protein that enables epithelial cells to securely attach to the basement membrane, which is composed of laminin proteins. This interaction is facilitated by a complex formed between ITG3beta1 and the tetraspanin CD151. When either ITG3beta1 or CD151 is mutated, it results in epidermolysis bullosa, a skin blistering condition caused by a defect in basement membrane attachment.
In this study, researchers utilized cryo-electron microscopy to capture the structure of the ITG3beta1-CD151 complex. Their findings indicate that a mutation in CD151 at the binding site disrupts complex formation within cells. Notably, the researchers discovered that knocking out CD151 through CRISPR technology leads to a surface export defect in ITG3beta1, but this defect can be corrected by reintroducing the wild-type CD151, but not when it is mutated.
The studies collectively elucidate the molecular mechanism behind CD151's binding to ITG3beta1, and demonstrate that CD151 plays a crucial role in facilitating ITG3beta1 surface export. This explanation offers a biochemical rationale for the loss-of-function phenotype observed in individuals with CD151 mutations, as seen in epidermolysis bullosa.
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