The function of ENSG00000115257 (PCSK4, proprotein convertase subtilisin/kexin type 4) is as follows. Proprotein convertase involved in the processing of hormone and other protein precursors at sites comprised of pairs of basic amino acid residues (By similarity). In males, important for ADAM2 processing as well as other acrosomal proteins with roles in fertilization and critical for normal fertilization events such as sperm capacitation, acrosome reaction and binding of sperm to zona pellucida (By similarity). Also plays a role in female fertility, involved in the regulation of trophoblast migration and placental development, may be through the proteolytical processing and activation of proteins such as IGF2 (PubMed:16040806). May also participate in folliculogenesis in the ovaries (By similarity). {ECO:0000250|UniProtKB:P29121, ECO:0000269|PubMed:16040806}.