1,3Fucosyltransferase VI is expressed in HepG2 cells and codistributed with  1,4galactosyltransferase I in the Golgi apparatus and monensin-induced swollen vesicles

The major [alpha]1,3fucosyltransferase activity in plasma, liver, and kidney is related to fucosyltransferase VI which is encoded by the FUT6 gene. Here we demonstrate the presence of [alpha]1,3fucosyltransferase VI ([alpha]3-FucT VI) in the human HepG2 hepatoma cell line by specific activity assays...

Full description

Saved in:
Bibliographic Details
Published in:Glycobiology (Oxford) 1999-11, Vol.9 (11), p.1273-1280
Main Authors: Borsig, L., Imbach, T., Hochli, M., Berger, E. G.
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The major [alpha]1,3fucosyltransferase activity in plasma, liver, and kidney is related to fucosyltransferase VI which is encoded by the FUT6 gene. Here we demonstrate the presence of [alpha]1,3fucosyltransferase VI ([alpha]3-FucT VI) in the human HepG2 hepatoma cell line by specific activity assays, detection of transcripts, and the use of specific antibodies. First, FucT activity in HepG2 cell lysates was shown to prefer sialyl-N-acetyllactosamine as acceptor substrate indicating expression of [alpha]3-FucT VI. RT-PCR analysis further confirmed the exclusive presence of the [alpha]3-FucT VI transcripts among the five human [alpha]3-FucTs cloned to date. [alpha]3-FucT VI was colocalized with [beta]1,4galactosyltransferase I ([beta]4-GalT I) to the Golgi apparatus by dual confocal immunostaining. Pulse/chase analysis of metabolically labeled [alpha]3-FucT VI showed maturation of [alpha]3-FucT VI from the early 43 kDa form to the mature, endoglycosidase H-resistant form of 47 kDa which was detected after 2 h of chase. [alpha]3-FucT VI was released to the medium and accounted for 50% of overall cell-associated and released enzyme activity. Release occurred by proteolytical cleavage which produced a soluble form of 43 kDa. Monensin treatment segregated [alpha]3-FucT VI from the Golgi apparatus to swollen peripheral vesicles where it was colocalized with [beta]4-GalT I while [alpha]2,6(N)sialyltransferase remained associated with the Golgi apparatus. Both constitutive secretion of [alpha]3-FucT VI and its monensin-induced relocation to vesicles analogous to [beta]4-GalT I suggest a similar post-Golgi pathway of both [alpha]3-FucT VI and [beta]4-GalT I.
ISSN:0959-6658
1460-2423
DOI:10.1093/glycob/9.11.1273