Members of this family consist of a distorted cytoplasmic helix that is partially absorbed into the plane of the lipid bilayer with a tilt angle of approximately 80 degrees from the membrane normal. They interact with the surface of the lipid bilayer, and contribute to the initiation of the apoptotic cascade on binding of the unstructured linker domain to dimethyltin [1].

1: Structure, dynamics, and membrane topology of stannin: a mediator of neuronal cell apoptosis induced by trimethyltin chloride. Buck-Koehntop BA, Mascioni A, Buffy JJ, Veglia G; J Mol Biol. 2005;354:652-665. PMID:16246365