Calcium-dependent phospholipid-binding protein that plays a role in calcium-mediated intracellular processes. Exhibits calcium-dependent cell membrane binding properties. Binds 3 Ca(2+) ions per C2 domain. Translocates to the cell membrane and the nucleus in a calcium-dependent manner. Colocalizes with CD2 at the cell membrane. Expressed in the brain. Expressed in neutrophil precursors from the bone marrow and peripheral blood (PubMed:12949241). The C2 domain 2, but not the C2 domain 1, is necessary for calcium-mediated membrane association. The linker region is necessary for calcium-dependent cell membrane association. Belongs to the copine family.