 Many other C2 domain families don't have calcium binding activity.C2 domains are frequently found coupled to enzymatic domains; for example, the C2 domain in PTEN, brings the phosphatase domain into contact with the plasma membrane, where it can dephosphorylate its substrate, phosphatidylinositol (3,4,5)-trisphosphate (PIP3), without removing it from the membrane - which would be energetically very costly.PTEN consists of two domains, a protein tyrosine phosphatase domain and a C2 domain.