eIF2B promotes eIF5 dissociation from eIF2•GDP to facilitate guanine nucleotide exchange for translation initiation

被引:62
作者
Jennings, Martin D. [1 ]
Zhou, Yu [1 ]
Mohammad-Qureshi, Sarah S. [1 ]
Bennett, David [1 ]
Pavitt, Graham D. [1 ]
机构
[1] Univ Manchester, Fac Life Sci, Manchester M13 9PT, Lancs, England
基金
英国生物技术与生命科学研究理事会; 英国惠康基金;
关键词
protein synthesis initiation; G-protein regulators; GEF; GDF; GDI; GCN4; MESSENGER-RNA; C-TERMINAL DOMAIN; FACTOR 2B COMPLEX; GDI DISPLACEMENT; CRYSTAL-STRUCTURE; CATALYTIC DOMAIN; RAB GTPASES; IDENTIFICATION; BINDING; INHIBITION;
D O I
10.1101/gad.231514.113
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Protein synthesis factor eIF2 delivers initiator tRNA to the ribosome. Two proteins regulate its G-protein cycle: eIF5 has both GTPase-accelerating protein (GAP) and GDP dissociation inhibitor (GDI) functions, and eIF2B is the guanine nucleotide exchange factor (GEF). In this study, we used protein-protein interaction and nucleotide exchange assays to monitor the kinetics of eIF2 release from the eIF2 center dot GDP/eIF5 GDI complex and determine the effect of eIF2B on this release. We demonstrate that eIF2B has a second activity as a GDI displacement factor (GDF) that can recruit eIF2 from the eIF2 center dot GDP/eIF5 GDI complex prior to GEF action. We found that GDF function is dependent on the eIF2B epsilon and eIF2B gamma subunits and identified a novel eIF2-eIF2B gamma interaction. Furthermore, GDF and GEF activities are shown to be independent. First, eIF2B GDF is insensitive to eIF2 alpha phosphorylation, unlike GEF. Second, we found that eIF2B gamma mutations known to disrupt GCN4 translational control significantly impair GDF activity but not GEF function. Our data therefore define an additional step in the protein synthesis initiation pathway that is important for its proper control. We propose a new model to place eIF2B GDF function in the context of efficient eIF2 recycling and its regulation by eIF2 phosphorylation.
引用
收藏
页码:2696 / 2707
页数:12
相关论文
共 54 条
[1]   Pi release from elF2, not GTP hydrolysis, is the step controlled by start-site selection during eukaryotic translation initiation [J].
Algire, MA ;
Maag, D ;
Lorsch, JR .
MOLECULAR CELL, 2005, 20 (02) :251-262
[2]   Direct binding of translation initiation factor eIF2γ-G domain to its GTPase- activating and GDP-GTP exchange factors eIF5 and eIF2Bε [J].
Alone, PV ;
Dever, TE .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2006, 281 (18) :12636-12644
[3]  
Amberg DC, 2005, Methods in yeast genetics: a Cold Spring Harbor Laboratory course manual
[4]   Conserved bipartite motifs in yeast eIF5 and eIF2Bε, GTPase-activating and GDP-GTP exchange factors in translation initiation, mediate binding to their common substrate eIF2 [J].
Asano, K ;
Krishnamoorthy, T ;
Phan, L ;
Pavitt, GD ;
Hinnebusch, AG .
EMBO JOURNAL, 1999, 18 (06) :1673-1688
[5]   Eukaryotic Initiation Factor 2 Phosphorylation and Translational Control in Metabolism [J].
Baird, Thomas D. ;
Wek, Ronald C. .
ADVANCES IN NUTRITION, 2012, 3 (03) :307-321
[6]   The crystal structure of the carboxy-terminal domain of human translation initiation factor eIF5 [J].
Bieniossek, Christoph ;
Schuetz, Patrick ;
Bumann, Mario ;
Limacher, Andreas ;
Uson, Isabel ;
Baumann, Ulrich .
JOURNAL OF MOLECULAR BIOLOGY, 2006, 360 (02) :457-465
[7]   Structure of the catalytic fragment of translation initiation factor 2B and identification of a critically important catalytic residue [J].
Boesen, T ;
Mohammad, SS ;
Pavitt, GD ;
Andersen, GR .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2004, 279 (11) :10584-10592
[8]  
DEVER TE, 1995, MOL CELL BIOL, V15, P6351
[9]   Identification of a GDI displacement factor that releases endosomal Rab GTPases from Rab-GDI [J].
DiracSvejstrup, AB ;
Sumizawa, T ;
Pfeffer, SR .
EMBO JOURNAL, 1997, 16 (03) :465-472
[10]   Ligand interactions with eukaryotic translation initiation factor 2: Role of the gamma-subunit [J].
Erickson, FL ;
Hannig, EM .
EMBO JOURNAL, 1996, 15 (22) :6311-6320