Phosphatidylinositol-glycan biosynthesis class X protein (PIGX)

Phosphatidylinositol-glycan biosynthesis class X protein (PIGX) is a stabilizing subunit essential for the GPI alpha-1,4-mannosyltransferase I enzyme complex, which is responsible for transferring the first mannose in the glycosylphosphatidylinositol (GPI) anchor biosynthetic pathway within the endoplasmic reticulum. PIGX itself ensures stability and enzymatic function of PIGM, the main catalytic subunit, and is required for proper cell surface expression of GPI-anchored proteins, which have roles in signal transduction, immune response, cell adhesion, and enzymatic functions. PIGX is upregulated in some cancers such as breast cancer, contributing to cell proliferation through negative regulation of tumor suppressor genes EHD2 and ZIC1. While there are currently no drugs known to directly target PIGX, its critical function makes it a potential future target for anticancer agents, though broad inhibition is likely to cause significant toxicity due to disruption of multiple essential cell-surface proteins.

Other names

GPI alpha-1,4-mannosyltransferase I, stabilizing subunitPIG-XFLJ20522phosphatidylinositol-glycan biosynthesis class X proteinGPI-mannosyltransferase subunit