Has phospholipase C (PLC) activity (PubMed:33621517, PubMed:34332077, PubMed:38388831). Shows specificity for phosphatidylethanolamine (1,2-diacyl-sn-glycero-3-phosphoethanolamine, PE), hydrolyzing PE to produce phosphoethanolamine and diacylglycerol (1,2-diacyl-sn-glycerol, DAG) (PubMed:34332077). This reaction might act as a regulatory switch to activate serine palmitoyltransferase (SPT) and promote sphingolipid metabolism (By similarity). Can also function as a ceramide phosphoethanolamine (N-acylsphingoid 1- phosphoethanolamine, CPE) synthase when intracellular ceramide levels are elevated (PubMed:19506037, PubMed:38388831). Binds the headgroup from PE, which is smaller and more hydrophilic than the phosphocholine headgroup transferred in the canonical sphingomyelin synthesis (SMS) reaction by SMS1 or SMS2, and transfers it on to the primary hydroxyl of a ceramide in the lumen of the endoplasmic reticulum (PubMed:19506037, PubMed:38388831). Plays a role as a ceramide sensor, helping to regulate ceramide homeostasis in the endoplasmic reticulum, which is critical for maintaining the integrity of the early secretory pathway (PubMed:19506037). {ECO:0000250|UniProtKB:Q9DA37, ECO:0000269|PubMed:19506037, ECO:0000269|PubMed:33621517, ECO:0000269|PubMed:34332077, ECO:0000269|PubMed:38388831}. This is the function of SAMD8 (sterile alpha motif domain containing 8, Ensembl gene identifier ENSG00000156671).