The N-terminal region of ABC50 interacts with eukaryotic initiation factor eIF2 and is a target for regulatory phosphorylation by CK2.
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.
Paytubi
Sonia
S
Division of Molecular Physiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
Morrice
Nicholas A
NA
Boudeau
Jerome
J
Proud
Christopher G
CG
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000378:metabolism*; D000409:Alanine / Q000737:chemistry; D001665:Binding Sites; D047390:Casein Kinase II / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D004926:Escherichia coli / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D019606:Phosphoamino Acids / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D012694:Serine / Q000737:chemistry
C115776:ABCF1 protein, human; D018528:ATP-Binding Cassette Transporters; D015852:Eukaryotic Initiation Factor-2; D019606:Phosphoamino Acids; D012694:Serine; D047390:Casein Kinase II; D000409:Alanine