GPI-anchor transamidase catalytic subunit (PIGK) (PIGK)

GPI-anchor transamidase catalytic subunit (PIGK) is a cysteine protease enzyme (C13 family) and the catalytic component of the multi-subunit GPI transamidase complex that is located in the endoplasmic reticulum membrane[1][2][3][4]. This enzyme catalyzes the transfer of a glycosylphosphatidylinositol (GPI) anchor to proteins, specifically by cleaving their C-terminal signal peptide and attaching the pre-assembled GPI anchor, a glycolipid that tethers many proteins to the cell surface[1][2][3][4]. GPI-anchored proteins are important in various biological functions including enzymatic activity, signaling, cell adhesion, and immune regulation[1][2]. PIGK functions via a caspase/legumain-like cysteine protease mechanism[1][2]. It interacts with other complex subunits (e.g., PIGT, GPAA1, PIGU, and PIGS)[2][4], and mutations have been linked to severe neurological disorders and potentially contribute to certain cancers[2][3]. PIGK is essential for normal GPI-anchor biosynthesis; deficiency leads to broad post-translational modification defects with clinical consequences[3]. Currently, no drugs are known to target PIGK directly, and it is not established as a therapeutic target, but its centrality in GPI-anchor biosynthesis and disease association make it of expanding biomedical interest[3][4].

Other names

GPI8hGPI8PIG-Kphosphatidylinositol glycan anchor biosynthesis class KGPI-anchor transamidase component PIGKGPI8 homologNEDHCAS