Cytoplasmic glycosylation

Iyer, S.P. and Hart, G.W. (2003) Dynamic nuclear and cytoplasmic glycosylation enzymes of 0-GlcNAc cycling. Biochemistry 42, 2493-2499. 

This is the most complex form of cytoplasmic glycosylation yet reported. Since both the native acceptor protein and the fucosyl transferase are novel, studying this pair in Dictyostelium should provide functional insights and the necessary tools to probe for counterparts in higher organisms. 

P. Teng-umnuay and C.M. West, Glycobiology, 1998, 8, 1105, Evidenee that a protein involved in ubiquitination is modified by a novel cytoplasmic glycosylation pathway. (Abstract)... 

Because membranes components participate in nearly every cell activity their structures are also dynamic and far from the equilibrium states that are most readily understood in biophysical terms. Newly synthesized bilayer lipids are initially associated with endoplasmic reticulum (Ch.3) whereas phospholipids initially insert into the cytoplasmic leaflet while cholesterol and sphingolipids insert into the luminal endoplasmic reticulum (ER) leaflet. Glycosylation of ceramides occurs as they transit the Golgi compartments, forming cerebrosides and gangliosides in the luminal leaflet. Thus, unlike model systems, the leaflets of ER membranes are asymmetric by virtue of their mode of biosynthesis. 

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