Tetraspanin CD151 regulates 6 1 integrin adhesion strengthening

The tetraspanin CD151 molecule associates specifically with laminin-binding integrins, including 6 1. To probe strength of 6 1-dependent adhesion to laminin-1, defined forces (0–1.5 nN) were applied to magnetic laminin-coated microbeads bound to NIH 3T3 cells. For NIH 3T3 cells bearing wild-type CD151, adhesion strengthening was observed, as bead detachment became more difficult over time. In contrast, mutant CD151 (with the C-terminal region replaced) showed impaired adhesion strengthening. Static cell adhesion to laminin-1, and detachment of beads coated with fibronectin or anti6 antibody were all unaffected by CD151 mutation. Hence, CD151 plays a key role in selectively strengthening 6 1 integrin-mediated adhesion to laminin-1.