CPNE8 is annotated in UniProt as a probable calcium-dependent phospholipid-binding protein that may play a role in calcium-mediated intracellular processes. Calcium-dependent membrane-binding proteins of this kind may regulate molecular events at the interface of the cell membrane and cytoplasm, and CPNE8 is considered to belong to that group. The annotation is cautious: the function is described as probable, and a subcellular location has not been annotated in UniProt.

The CPNE8 protein belongs to the copine family. According to the NCBI Gene summary, the gene is one of several that encode a calcium-dependent protein containing two N-terminal type II C2 domains and an integrin A domain-like sequence in the C-terminus. C2 domains are commonly associated with calcium-dependent lipid binding, which fits the phospholipid-binding activity proposed for copines. The CPNE8 gene is the mouse Cpne8 counterpart's human ortholog, and the mouse gene is the natural reference for comparative work.

HGNC classifies the gene under the Copines gene group, with the approved name copine 8 and the previous name copine VIII. Researchers studying CPNE8 usually place it alongside other copine family members when investigating calcium signalling at membranes. Because the available functional annotation is limited, work on CPNE8 antibody, CPNE8 ELISA kit or CPNE8 protein detection typically begins with defining where and when the protein is expressed in the system of interest.