Early and late functions associated with the Golgi apparatus reside in distinct compartments - PubMed (original) (raw)

Early and late functions associated with the Golgi apparatus reside in distinct compartments

W G Dunphy et al. Proc Natl Acad Sci U S A. 1981 Dec.

Abstract

Enzymes that catalyze the two successive stages of Golgi-associated processing of asparagine-linked oligosaccharides distributed differently when membranes from Chinese hamster ovary cells were centrifuged in a sucrose density gradient. A mannosidase that removes only outer, alpha-1,2-linked mannose residues from the precursor oligosaccharides of the vesicular stomatitis viral G protein (to yield a "trimmed" oligosaccharide core) was separated from enzymes (galactosyl- and sialyltransferases) that act in the later, terminal stage of glycosylation. Freshly acylated G protein with newly trimmed oligosaccharides banded in the distribution of early-acting membranes, defined by the mannosidase, whereas G protein pulse-labeled with [3H]galactose distributed in the profile of the late-acting membranes. G protein present in the early-acting membranes in crude fractions could be terminally glycosylated by incubation with exogenous Golgi membranes in vitro; G protein lost its ability to be processed in vitro as it appeared to enter the late-acting membranes in vivo. These experiments reveal the existence of two distinct compartments through which intracellularly transported proteins such as G pass in sequence as Golgi-associated processes are carried out. It is likely that these compartments consist of cisternae on the cis and trans sides of the Golgi stack.

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References

    1. J Cell Biol. 1981 Apr;89(1):162-8 - PubMed
    1. J Biol Chem. 1977 Feb 10;252(3):1107-16 - PubMed
    1. Proc Natl Acad Sci U S A. 1981 Jan;78(1):293-7 - PubMed
    1. J Biol Chem. 1980 Apr 25;255(8):3334-9 - PubMed
    1. J Cell Biol. 1980 Jan;84(1):87-101 - PubMed

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