RGD Reference Report - Effect of GTP on the dolichol pathway for protein glycosylation in rat liver microsomes. - Rat Genome Database

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Effect of GTP on the dolichol pathway for protein glycosylation in rat liver microsomes.

Authors: Bossuyt, X  Blanckaert, N 
Citation: Bossuyt X and Blanckaert N, Biochem J. 1993 Dec 15;296 ( Pt 3):633-7.
RGD ID: 1624315
Pubmed: (View Article at PubMed) PMID:8280061

Incubation of native rat liver microsomes with GTP resulted in enhanced incorporation of N-acetylglucosamine (GlcNAc) from UDP-GlcNAc into lipid acceptors. The stimulation of GlcNAc transfer by GTP was specific for GTP; ATP exerted no effect. The GTP effect was blocked by a non-hydrolysable GTP analogue guanosine 5'-[beta gamma-imido]triphosphate, indicating that GTP hydrolysis was crucial. Though dolichyl pyrophosphate NN'-diacetylchitobiose [Dol-PP-(GlcNAc)2] was the main radiolabelled product formed upon incubation of GTP-treated microsomes with UDP-GlcNAc, GTP selectively stimulated UDP-GlcNAc:dolichyl phosphate (Dol-P) N-acetylglucosaminyl 1-phosphotransferase (N-acetylglucosaminyl 1-phosphotransferase). This conclusion was reached on the basis of experiments in which tunicamycin was used to selectively inhibit N-acetylglucosaminyl 1-phosphotransferase. The enhanced transformation of Dol-P to dolichyl pyrophosphate N-acetylglucosamine (Dol-PP-GlcNAc) by GTP ultimately led to enhanced protein glycosylation. GTP-induced stimulation of GlcNAc incorporation in lipid and protein by GTP was observed also in microsomes fully permeabilized with Staph. aureus alpha-toxin. These findings refute the previous proposal [Godelaine, Beaufay, Wibo and Ravoet (1983) J. Cell Biol. 97, 340-350] that increased membrane permeability constitutes the mechanism whereby GTP activates the reactions of the dolichol pathway.

Gene Ontology Annotations    

Biological Process

Cellular Component

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Dpagt1  (dolichyl-phosphate N-acetylglucosaminephosphotransferase 1)

Additional Information