Brought to you by Portland Press Ltd.
Published on behalf of the International Federation for Cell Biology
Cancer Cell death Cell cycle Cytoskeleton Exo/endocytosis Differentiation Division Organelles Signalling Stem cells Trafficking
Cell Biology International (1997) 21, 223–228 (Printed in Great Britain)
EXPRESSION OF A CYTOPLASMICALLY EPITOPE-TAGGED, HUMAN GOLGI GLYCOSYLTRANSFERASE IN HOMOLOGOUS CELLS RESULTS IN MISLOCALIZATION OF MULTIPLE GOLGI PROTEINS
WEI YANG and BRIAN STORRIE
Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0308, U.S.A.


Abstract

We have compared the effect of mislocalization of a Golgi glycosyltransferase in heterologous and homologous cell systems on the distribution of other Golgi-associated proteins. Myc-spacer-human N-acetylglucosaminyltransferase I (NAGT-I), an N-terminally epitope-tagged NAGT-I, in which the first added negatively charged amino acid is in position 13, localizes to the endoplasmic reticulum (ER) by immunofluorescence when expressed in monkey (Vero) or human (HeLa) cells. When myc-spacer-human NAGT-I was expressed in Vero cells, the distribution of the Golgi-associated coat protein, β-COP, was concentrated juxtanuclearly and undisturbed relative to control. When myc-spacer-human NAGT-I was expressed in HeLa cells, however, both endogenous β-COP and GalT were no longer concentrated in a juxtanuclear manner but were rather cytoplasmically distributed as was the myc-tagged human NAGT-I. Based on these observations, we suggest that extensive interactions between proteins that normally show overlapping distributions between the medial Golgi stack and trans Golgi/TGN are possible. Moreover, we suggest that small differences in sequence may play a large role in potentiating interactions of Golgi complex proteins.


Key words: Golgi complex, glycosyltransferase, epitope tagging, kin recognition.

f1To whom correspondence should be addressed.


doi:10.1006/cbir.1997.0138


ISSN Print: 1065-6995
ISSN Electronic: 1095-8355
Published by Portland Press Limited on behalf of the International Federation for Cell Biology (IFCB)