Glycosylphosphatidylinositol-glycan (GPI) is an anchor to specific cell surface proteins known as GPI-anchored proteins (APs) that are localized in lipid rafts and may act as cell co-receptors, enzymes and adhesion molecules. The present review investigated the significance of GPI biosynthesis class phosphatidylinositol-glycan
(PIG)M
and
PIGX
in GPI synthesis and their implications in human health conditions.
PIGM
encodes GPI-mannosyltransferase I (MT-I) enzyme that adds the first mannose to the GPI core structure.
PIGX
encodes the regulatory subunit of GPI-MT-I. The present review summarizes characteristics of the coding sequences of
PIGM
and
PIGX
, and their expression in humans, as well as the relevance of GPI-MT-I and the regulatory subunit in maintaining the presence of GPI-APs on the cell surface and their secretion. In addition, the association of
PIGM
mutations with paroxysmal nocturnal hemoglobinuria and certain types of GPI-deficiency disease and the altered expression of
PIGM
and
PIGX
in cancer were also reviewed. In addition, their interaction with other proteins was described, suggesting a complex role in cell biology.
PIGM
and
PIGX
are critical genes for GPI synthesis. Understanding gene and protein regulation may provide valuable insights into the role of GPI-APs in cellular processes.