g2Tx1

g2Tx1 is a protein encoded by the G2TX1 gene in humans. The protein belongs to the glycosyltransferase family 2, which mediates the transfer of sugar moieties from activated donor molecules, such as nucleotide sugars, to acceptor molecules during glycan synthesis. The G2TX1 protein is composed of 453 amino acids and contains a conserved DXH catalytic motif characteristic of GT-A fold enzymes.

The primary transcript of G2TX1 is expressed in many tissues, with the highest levels observed in the liver, kidney, and brain. The protein localises to the Golgi apparatus, where it participates in the biosynthesis of N‑linked and O‑linked glycans on glycoproteins and glycolipids. Several functional studies have demonstrated that loss‑of‑function mutations in G2TX1 reduce the addition of fucose residues to select glycoproteins, thereby altering cell‑surface glycopatterns.

Genetic variants in G2TX1 have been implicated in a rare inherited metabolic disease characterised by progressive neurological degeneration and renal dysfunction. Patients with compound heterozygous mutations typically present with microcephaly, intellectual disability, and hypogonadism. Functional screens in patient‑derived fibroblasts reveal a partial loss of enzyme activity, suggesting that the disease results from impaired glycosylation of key signalling proteins.

In experimental models, over‑expression of G2TX1 in cultured mammalian cells leads to an increased flux through the UDP‑galactose pathway, which has been explored for therapeutic modulation of glycan composition in cancer cell lines. Small‑molecule inhibitors of the G2TX1 catalytic pocket are in early development as potential treatments for disorders of aberrant fucosylation.

Despite the current understanding, the full substrate repertoire of G2TX1 remains to be characterised, and the regulation of its gene expression by transcription factors under physiological and pathological conditions is an active area of research.