Members of this family are predominantly found in phosphoinositide-specific phospholipase C. They adopt a structure consisting of a core of four alpha helices, in an EF like fold, and are required for functioning of the enzyme [1].

1: C2 domain conformational changes in phospholipase C-delta 1. Grobler JA, Essen LO, Williams RL, Hurley JH; Nat Struct Biol. 1996;3:788-795. PMID:8784353