In molecular biology, copines is a name for the group of human proteins that includes members such as CPNE1, CPNE4, CPNE6, and CPNE8.
[2] The domain structure of these 55 kDa [3] proteins suggests that they may have a role in membrane trafficking in some prokaryotes as well as eukaryotes.
[4] Copines contains two C2 domains which play a role in signal transduction by binding to calcium, phospholipids, or polyphosphates.
[5][4] The core domain located at the C-terminus part of the copine is found to have a unique and conserved primary sequence.
[3] This similarity in function involves serving as a binding site for target proteins, and is supported by evidence that the copine core domain exhibits secondary and tertiary structures comparable to the integrin A domain.