LFA-1 is a heterodimeric integrin composed of CD11a and CD18 subunits. Both subunits contain short cytoplasmic domains, transmembrane domains, and large extracellular domains. (B) CD11a β-propeller. The CD11a β-propeller consists of seven sheets (W1–W7), each comprised of four strands (S1–S4). (C) Reported LtxA Binding Sites. LtxA has been reported to target the CD11a β-propeller, the CD18 I-EGF domains, and the cytoplasmic domains of both CD11a and CD18. Each reported binding site is highlighted in red.