The function of PLCZ1 (phospholipase C zeta 1, Ensembl gene identifier ENSG00000139151) is as follows. The production of the second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3) is mediated by activated phosphatidylinositol-specific phospholipase C enzymes. In vitro, hydrolyzes PtdIns(4,5)P2 in a Ca(2+)-dependent manner. Triggers intracellular Ca(2+) oscillations in oocytes solely during M phase and is involved in inducing oocyte activation and initiating embryonic development up to the blastocyst stage. Is therefore a strong candidate for the egg-activating soluble sperm factor that is transferred from the sperm into the egg cytoplasm following gamete membrane fusion. May exert an inhibitory effect on phospholipase-C-coupled processes that depend on calcium ions and protein kinase C, including CFTR trafficking and function. {ECO:0000250|UniProtKB:Q8K4D7, ECO:0000269|PubMed:12416999, ECO:0000269|PubMed:14697805, ECO:0000269|PubMed:15579586, ECO:0000269|PubMed:26721930, ECO:0000305}.