|Cancer||Cell death||Cell cycle||Cytoskeleton||Exo/endocytosis||Differentiation||Division||Organelles||Signalling||Stem cells||Trafficking|
Cell Biology International (1997) 21, 223228 (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.
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.
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