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Title: Architecture of coatomer: Molecular characterization of delta-COP and protein interactions within the complex
Authors: Faulstich, D
Auerbach, S
Orci, L
Ravazzola, M
Wegchingel, S
Lottspeich, F
Stenbeck, G
Harter, C
Wieland, FT
Tschochner, H
Keywords: ADP-ribosylation factor (ARF)
Issue Date: 1996
Publisher: The Rockefeller University Press
Citation: The Journal of Cell Biology, 135(1): 53-61, 1996
Abstract: Coatomer is a cytosolic protein complex that forms the coat of COP I-coated transport vesicles. In our attempt to analyze the physical and functional interactions between its seven subunits (coat proteins, [COPs] alpha-zeta), we engaged in a program to clone and characterize the individual coatomer subunits. We have now cloned, sequenced, and overexpressed bovine alpha-COP, the 135-kD subunit of coatomer as well as delta-COP, the 57-kD subunit and have identified a yeast homolog of delta-COP by cDNA sequence comparison and by NH2-terminal peptide sequencing. delta-COP shows homologies to subunits of the clathrin adaptor complexes AP1 and AP2. We show that in Golgi-enriched membrane fractions, the protein is predominantly found in COP I-coated transport vesicles and in the budding regions of the Golgi membranes. A knock-out of the delta-COP gene in yeast is lethal. Immunoprecipitation, as well as analysis exploiting the two-hybrid system in a complete COP screen, showed physical interactions between alpha- and epsilon-COPs and between beta- and delta-COPs. Moreover, the two-hybrid system indicates interactions between gamma- and zeta-COPs as well as between alpha- and beta' COPs. We propose that these interactions reflect in vivo associations of those subunits and thus play a functional role in the assembly of coatomer and/or serve to maintain the molecular architecture of the complex.
Description: Copyright © 2011 by The Rockefeller University Press.
ISSN: 0021-9525
Appears in Collections:Biological Sciences
Dept of Life Sciences Research Papers

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