UDP-GlcNAc transport across the golgi membrane: Electroneutral exchange for dianionic UMP

Journal Article · Tue Jan 09 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00453a006· OSTI ID:6941298

Waldman, B C; Rudnick, G ^[1]

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1. Yale Univ. School of Medicine, New Haven, CT (USA)

The authors have examined the coupling and charge stoichiometry for UDP-GlcNAc transport into Golgi-enriched vesicles from rat liver. In the absence of added energy sources, these Golgi vesicles concentrate UDP-GlcNAc at least 20-fold, presumably by exchange with endogenous nucleotides. Under the conditions used, extravesicular degradation of UDP-GlcNAc has been eliminated, and less than 15% of the internalized radioactivity becomes associated with endogenous macromolecules. Of the remaining intravesicular label, 85% remains unmetabolized UDP-({sup 3}H)GlcNAc, and approximately 15% is hydrolyzed to ({sup 3}H)GlcNAc-1-phosphate. Efflux of accumulated UDP-({sup 3}H)GlcNAc is induced by addition of nonradioactive UDP-GlcNAc, UMP, UDP, or UDP-galactose to the external medium. Permeabilization of Golgi vesicles causes a rapid and nearly complete loss of internal UDP-({sup 3}H)GlcNAc, indicating that the results reflect transport and binding. Moreover, transport of UDP-({sup 3}H)GlcNAc into these Golgi vesicles was stimulated up to 5-fold by mechanically preloading vesicles with either UDP-GlcNAc or UMP. The response of UMP/UMP exchange and UMP/UDP-GlcNAc exchange to alterations in intravesicular and extravesicular pH suggests that UDP-GlcNAc enters the Golgi apparatus in electroneutral exchange with the dianionic form of UMP.

• OSTI ID: 6941298
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:1; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
BODY
CARBOHYDRATES
CELL CONSTITUENTS
CHALCOGENIDES
CHROMATOGRAPHY
DIGESTIVE SYSTEM
GALACTOSE
GLANDS
GLYCOSIDES
HEXOSES
HYDROGEN COMPOUNDS
ION EXCHANGE CHROMATOGRAPHY
LIVER
MAMMALS
MEMBRANE TRANSPORT
MONOSACCHARIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PERMEABILITY
PH VALUE
RATS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
TRITIUM COMPOUNDS
TRITIUM OXIDES
UDPG
UMP
VERTEBRATES