Glycosylation mutations of serine/threonine-linked oligosaccharides in low-density lipoprotein receptor: Indispensable roles of O-glycosylation

Abstract

ABSTRACT The low-density lipoprotein (LDL) receptor is a surface glycoprotein that mediates the cellular uptake of LDL, a cholesterol-carrying plasma protein (Goldstein et al. 1985). After receptor-mediated endocytosis of LDL, LDL receptor recycles to the cell surface from the acid compartment, the endosome, and LDL is then transported and degraded in lysosomes where the cholesterol ester core is hydrolysed and from which the unesterified cholesterol is released. The cholesterol molecules from LDL regulate de novo cholesterol biosynthesis and LDL receptor expression. Mutations in the receptor gene for the LDL receptor impair LDL uptake into cells and cause familial hypercholesterolemia (FH) because of the lack of normal regulation of cholesterol metabolism (Goldstein et al. 1985).