ABC50 is an ABC (ATP-binding cassette) protein which, unlike most ABC proteins, lacks membrane-spanning domains. ABC50 interacts with eIF2 (eukaryotic initiation factor 2), a protein that plays a key role in translation initiation and in its control, and in regulation of ribosomes. Here, we establish that the interaction of ABC50 with eIF2 involves features in the N-terminal domain of ABC50, the region of ABC50 that differs most markedly from other ABC proteins. This region also shows no apparent similarity to the eIF2-binding domains of other partners of eIF2. In contrast, the N-terminus of ABC50 cannot bind to ribosomes by itself, but it can in conjunction with one of the nucleotide-binding domains. We demonstrate that ABC50 is a phosphoprotein and is phosphorylated at two sites by CK2. These sites, Ser-109 and Ser-140, lie in the N-terminal part of ABC50 but are not required for the binding of ABC50 to eIF2. Expression of a mutant of ABC50 in which both sites are mutated to alanine markedly decreased the association of eIF2 with 80S ribosomal and polysomal fractions.
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Research Article|
December 11 2007
The N-terminal region of ABC50 interacts with eukaryotic initiation factor eIF2 and is a target for regulatory phosphorylation by CK2
Sonia Paytubi;
Sonia Paytubi
*Division of Molecular Physiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K.
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Nicholas A. Morrice;
Nicholas A. Morrice
†Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K.
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Jerome Boudeau;
Jerome Boudeau
†Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K.
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Christopher G. Proud
Christopher G. Proud
1
*Division of Molecular Physiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K.
‡Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
1To whom correspondence should be addressed (email cgpr@interchange.ubc.ca)
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Publisher: Portland Press Ltd
Received:
June 18 2007
Revision Received:
September 24 2007
Accepted:
September 26 2007
Accepted Manuscript online:
September 26 2007
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© The Authors Journal compilation © 2008 Biochemical Society
2008
Biochem J (2008) 409 (1): 223–231.
Article history
Received:
June 18 2007
Revision Received:
September 24 2007
Accepted:
September 26 2007
Accepted Manuscript online:
September 26 2007
Citation
Sonia Paytubi, Nicholas A. Morrice, Jerome Boudeau, Christopher G. Proud; The N-terminal region of ABC50 interacts with eukaryotic initiation factor eIF2 and is a target for regulatory phosphorylation by CK2. Biochem J 1 January 2008; 409 (1): 223–231. doi: https://doi.org/10.1042/BJ20070811
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