GLCE (glucuronic acid epimerase), also known as HSEPI (heparin/heparan sulfate:glucuronic acid C5-epimerase) or D-glucuronyl C5-epimerase, is a single-pass type II membrane protein that is part of the golgi apparatus and, through its enzymatic activity, is essential for proper biological function of heparan sulphate (HS). GLCE epimerizes D-glucuronic acid into L-iduronic acid of HS, thus changing the specificity of HS and allowing it to bind to cytokines and growth factors. GLCE is a target of the beta-catenin–TCF4 transactivation complex; an essential component in the Wnt/APC/beta-catenin signaling pathway that is upregulated in colon carcinoma cells. The enzymatic activity of GLCE is enhanced by overexpression of beta-catenin–TCF4, suggesting a possible role for GLCE in the dysregulation of proper signaling pathways; a dysregulation that leads to the development of human epithelial tumors.
Function:
Glucuronic Acid Epimerase (GLCE) is responsible for epimerization of D-glucuronic acid (GlcA) to L-iduronic acid (IdoA) of Heparan sulfate (HS), which endows the nascent polysaccharide chain with the ability to bind growth factors and cytokines (Ghiselli and Agrawal, 2005 [PubMed 15853773]).
Subunit:
Interacts with HS2ST1 (By similarity).
Subcellular Location:
Golgi apparatus membrane; Single-pass type II membrane protein
Similarity:
Belongs to the D-glucuronyl C5-epimerase family.
SWISS:
O94923
Gene ID:
26035
Database links:
Entrez Gene: 26035 Human
Entrez Gene: 93683 Mouse
Omim: 612134 Human
SwissProt: O94923 Human
SwissProt: Q9EPS3 Mouse
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