This family contains the extracellular repeat that is found in up to seven copies in alpha integrins. This repeat has been predicted to fold into a beta propeller structure [1]. The repeat is called the FG-GAP repeat after two conserved motifs in the repeat [1]. The FG-GAP repeats are found in the N terminus of integrin alpha chains, a region that has been shown to be important for ligand binding [2]. A putative Ca2+ binding motif is found in some of the repeats.

1: Folding of the N-terminal, ligand-binding region of integrin alpha- subunits into a beta-propeller domain. Springer TA; Proc Natl Acad Sci U S A 1997;94:65-72. PMID:8990162

2: Integrin-mediated cell adhesion: the extracellular face. Loftus JC, Smith JW, Ginsberg MH; J Biol Chem 1994;269:25235-25238. PMID:7929213