Calcium-dependent phospholipid-binding protein that plays a role in calcium-mediated intracellular processes (PubMed:14674885). Involved in the TNF receptor signaling pathway in a calcium-dependent manner (PubMed:14674885). Exhibits calcium-dependent phospholipid binding properties (PubMed:19539605, PubMed:9430674). Plays a role in neuronal progenitor cell differentiation; induces neurite outgrowth via a AKT-dependent signaling cascade and calcium-independent manner (PubMed:23263657, PubMed:25450385). May recruit target proteins to the cell membrane in a calcium-dependent manner (PubMed:12522145). May function in membrane trafficking (PubMed:9430674). Involved in TNF- induced NF-kappa-B transcriptional repression by inducing endoprotease processing of the transcription factor NF-kappa-B p65/RELA subunit (PubMed:18212740). Also induces endoprotease processing of NF-kappa-B p50/NFKB1, p52/NFKB2, RELB and REL (PubMed:18212740). {ECO:0000269|PubMed:12522145, ECO:0000269|PubMed:14674885, ECO:0000269|PubMed:18212740, ECO:0000269|PubMed:19539605, ECO:0000269|PubMed:23263657, ECO:0000269|PubMed:25450385, ECO:0000269|PubMed:9430674}. This is the function of Ensembl gene identifier ENSG00000214078 (CPNE1, copine 1).