title: Processing of VSVG protein is not a rate-limiting step for its efflux from the Golgi complex.
abstract: The secretory membrane system is comprised of membrane-bound organelles defined by specific sets of proteins that function in sequential modification of cargo proteins and lipids. This processing of cargo proteins and lipids is coupled to their secretory transport. Here, we investigated the effect of inhibiting N-glycan processing by swainsonine, an inhibitor of Golgi alpha1,2-mannosidase-II, on secretory transport of the thermo-reversible tsO45 mutant of vesicular stomatitis virus glycoprotein tagged with green fluorescent protein (VSVG-FP). Quantitative analysis using kinetic modeling combined with live cell imaging was used to derive the rate coefficients that delineate secretory transport of VSVG-FP. We found that neither inhibition of N-glycan processing nor elimination by mutagenesis of the first of the two asparagine-linked glycans had any significant effect on the rate of VSVG-FP transport through the Golgi. These data suggest that at least for VSVG, the multi-enzymatic process of N-glycan modification does not comprise a rate-limiting step for its Golgi efflux.
authors.affiliation: Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Genady
authors.initials: G
authors.lastname: Vasserman
authors.forename: Lee Goldstein
authors.initials: LG
authors.lastname: Magal
authors.forename: Jeanne
authors.initials: J
authors.lastname: Shepshelovich
authors.forename: Eyal
authors.initials: E
authors.lastname: Elifaz
authors.forename: Koret
authors.initials: K
authors.lastname: Hirschberg
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003198:Computer Simulation; D005089:Exocytosis / Q000502:physiology*; D006056:Golgi Apparatus / Q000378:metabolism*; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D021381:Protein Transport / Q000502:physiology / Q000528:radiation effects; D014759:Viral Envelope Proteins / Q000378:metabolism*
chemical_list: C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins