CALM Protein Domain

The CALM (Clathrin Assembly Lymphoid Myeloid) domain, also known as ANTH, has a structure similar to the ENTH domain apart from the addition of one or more α-helices. Although both the CALM and ENTH domains bind PtdIns(4,5)P2 with high specificity, they differ in the manner in which they bind. ENTH domains bind PtdIns(4,5)P2 within a pocket, while ANTH domains lack a well defined binding pocket and instead use surface exposed basic residues to coordinate binding. CALM domain containing proteins include AP180 and CALM, which are implicated in the formation of clathrin-coated pits.