Self-regulation of MGAT4A and MGAT4B activity toward glycoproteins through interaction of lectin domain with their own -glycans.

-Acetylglucosaminyltransferases-IVa (GnT-IVa or MGAT4A) and -IVb (MGAT4B) are glycosyltransferase isozymes synthesizing the β1,4-GlcNAc branch in -glycans, a glycan structure involved in diabetes. These enzymes uniquely have a non-catalytic lectin domain, which selectively recognizes the GnT-IV product -glycan branch, but the role of this lectin domain has remained unclear. Here, using UDP-Glo enzyme assays, we discovered that this domain is required for activity toward glycoprotein substrates but not toward free glycans.

The efficacy of simple oral nutritional supplements versus usual care in postoperative patients with gastric cancer: study protocol for a multicenter, open-label, parallel, randomized controlled trial.

Background: Body weight loss (BWL) after gastrectomy impact on the short- and long-term outcomes. Oral nutritional supplement (ONS) has potential to prevent BWL in patients after gastrectomy. However, there is no consistent evidence supporting the beneficial effects of ONS on BWL, muscle strength and health-related quality of life (HRQoL).

The K346T mutant of GnT-III bearing weak in vitro and potent intracellular activity.

Background: N-Acetylglucosaminyltransferase-III (GnT-III, also designated MGAT3) catalyzes the formation of a specific N-glycan branch, bisecting GlcNAc, in the Golgi apparatus. Bisecting GlcNAc is a key residue that suppresses N-glycan maturation and is associated with the pathogenesis of cancer and Alzheimer's disease. However, it remains unclear how GnT-III recognizes its substrates and how GnT-III activity is regulated in cells.

LacdiNAc synthase B4GALNT3 has a unique PA14 domain and suppresses N-glycan capping.

Structural variation of N-glycans is essential for the regulation of glycoprotein functions. GalNAcβ1-4GlcNAc (LacdiNAc or LDN), a unique subterminal glycan structure synthesized by B4GALNT3 or B4GALNT4, is involved in the clearance of N-glycoproteins from the blood and maintenance of cell stemness. Such regulation of glycoprotein functions by LDN is largely different from that by the dominant subterminal structure, N-acetyllactosamine (Galβ1-4GlcNAc, LacNAc).