Copine

In molecular biology, copines is a name for the group of human proteins that includes members such as CPNE1, CPNE4, CPNE6, and CPNE8. These are highly conserved, calcium-dependent membrane proteins found in a variety of eukaryotes. The domain structure of these 55 kDa proteins suggests that they may have a role in membrane trafficking in some prokaryotes as well as eukaryotes. Copines contains two C2 domains which play a role in signal transduction by binding to calcium, phospholipids, or polyphosphates. The core domain located at the C-terminus part of the copine is found to have a unique and conserved primary sequence. The function of the core domain is still uncertain, however, researchers believe it has a similar function to the "A domain" in integrins.