Expression, purification, and enzymatic characterization of human UDP-glucose:glycoprotein glucosyltransferase-selenoprotein F complex from Sf9 insect cells.

Appropriate functioning of the glycoprotein quality control system in the endoplasmic reticulum is crucial for maintaining cellular homeostasis. UDP-glucose:glycoprotein glucosyltransferase 1 (UGGT1) is a key component of this system, serving as a "folding sensor" by recognizing the partially folded state of cognate glycoproteins and reglucosylating their deglucosylated N-glycans. Notably, UGGT1 is known to form heterodimers with Selenoprotein F (SelenoF), although the mechanism underlying the complex formation remains unclear.