Peptidase family M28; Endoplasmic reticulum metallopeptidase 1 (ERMP1; Felix-ina, FXNA or Fxna peptidase; KIAA1815) subfamily. ERMP1 is a multi-pass membrane protein located in the endoplasmic reticulum membrane. In humans, Fxna may play a crucial role in processing proteins required for the organization of somatic cells and oocytes into discrete follicular structures, although which proteins are hydrolyzed has not yet been determined. Another member of this subfamily is the 24-kDa vacuolar protein (VP24) which is probably involved in the formation of intravacuolar pigmented globules (cyanoplasts) in highly anthocyanin-containing vacuoles; however, the biological function of the C-terminal region which includes the putative transmembrane metallopeptidase domain is unknown.
Jiyao W et al.(2023). "The conserved domain database in 2023.",