We used immunoelectron microscopy to localize glucosidase II in pig hepatocytes. The enzyme trims the two inner alpha 1,3-linked glucoses from N-linked oligosaccharide precursor chains of glycoproteins. Immunoreactive enzyme was concentrated in rough (RER) and smooth (SER) endoplasmic reticulum but not detectable in Golgi apparatus cisternae. Transitional elements of RER and smooth membraned structures close to Golgi apparatus cisternae contained labeling for glucosidase II. Specific labeling was also found in autophagosomes. These results indicate strongly that glucosidase II acts on glycoproteins before their transport to, and processing in Golgi apparatus cisternae, and suggest that an important transitional region for glucosidase II exists between RER and Golgi apparatus cisternae. Degradation in autophagolysosomes could form a normal catabolic pathway for glucosidase II.
Article| June 01 1986
Immunolocalization of the oligosaccharide trimming enzyme glucosidase II.
J M Lucocq
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1986) 102 (6): 2137–2146.
J M Lucocq, D Brada, J Roth; Immunolocalization of the oligosaccharide trimming enzyme glucosidase II.. J Cell Biol 1 June 1986; 102 (6): 2137–2146. doi: https://doi.org/10.1083/jcb.102.6.2137
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