ライフサイエンスコーパス: eIF1

1 eIF1 also mediates release of P site tRNA, whereas eIF3j

2 eIF1 and eIF1A are key players in assembly of 43S.mRNA c

3 eIF1 binds simultaneously to eIF4G and eIF3c in vitro, a

4 eIF1 interacts with the region (60-137) that immediately

5 eIF1 is a universally conserved translation factor that

6 eIF1 prevents the irreversible GTP hydrolysis that commi

7 eIF1 release in response to start codon recognition is a

8 Eukaryotic initiation factor 1 (eIF1) is a low molecular weight factor critical for stri

9 eukaryotic translation initiation factor 1 (eIF1), eIF1A, and eIF2beta all increase SUI1 expression

10 timulated by eukaryotic initiation factor 1 (eIF1), eIF1A, eIF3, and eIF5, and the resulting preiniti

11 tis elegans translation initiation factor 1 (eIF1).

12 und to eukaryotic initiation factor (eIF) 3, eIF1, eIF1A, and an eIF2/GTP/Met-tRNAi(Met) ternary comp

13 d eIF3 in the 40S preinitiation complex (40S.eIF1.eIF1A.eIF3.Met-tRNA(i).eIF2.GTP) and the subsequent

14 (93-97)ASQAA (abbreviated 93-97) accelerates eIF1 dissociation and P(i) release from reconstituted pr

15 Although eIF1 and eIF1A promote scanning, eIF1 and possibly the C

16 Although eIF1 autoregulates by discriminating against poor contex

17 F1 on the 40S subunit suggests that although eIF1 is unable to inspect the region of initiation codon

18 An eIF1 substitution that should strengthen the eIF2beta:eI

19 Thus, eIF2beta anchors eIF1 and TC to the open complex, enhancing PIC assembly

20 formation of this cap-proximal complex, and eIF1 weakly promotes formation of a 48S ribosomal comple

21 so a marked reduction in 40 S-bound eIF2 and eIF1, consistent with an important role for RLI1 in asse

22 Therefore eIF3 and eIF1 dissociate from 40S subunits during, rather than be

23 eIF4G1 dynamically interacts with eIF4E and eIF1.

24 anonical initiation factors except eIF4E and eIF1.

25 -1 reduced the interaction between eIF4G and eIF1 in vitro.

26 lso reduces the levels of 40S-bound eIF5 and eIF1 and increases leaky scanning at the GCN4 uORF1.

27 on with the AUG recognition factors eIF5 and eIF1.

28 us of NIP1 can bind concurrently to eIF5 and eIF1.

29 The eIF2, eIF5, and eIF1 all have been implicated in stringent selection of

30 (MFC), comprised of these three factors and eIF1, supporting a mechanism of coupled 40S binding by M

31 that closes upon start codon recognition and eIF1 release to stabilize ternary complex binding and cl

32 hich justifies the possibility that YciH and eIF1 might have a common evolutionary origin as initiati

33 le for the factor's activity in antagonizing eIF1 binding to the PIC.

34 hat ribosomes are three times as abundant as eIF1, eIF2 and eIF5, while eIF3 is half as abundant as t

35 The direct interaction at eIF1-KH also places eIF5 near the decoding site of the 4

36 F1 exacerbated the tif5-7A phenotype because eIF1 forms unusual inhibitory complexes with a hyperstoi

37 NIP1-NTD coordinates an interaction between eIF1 and eIF5 that inhibits GTP hydrolysis at non-AUG co

38 g the core of the platform domain that binds eIF1 and eIF2, and A1193U, changing the h31 loop located

39 complex contained, in addition to eIF3, both eIF1 and eIF1A in a 1:1 stoichiometry with respect to th

40 mplex was stabilized by the presence of both eIF1 and eIF3.

41 These studies demonstrate that both eIF1 and eIF1A are capable of binding to the 40S subunit

42 ined 3D reconstructions of 40S bound to both eIF1 and eIF1A, and with each factor alone.

43 -tRNA(iMet) recruitment were destabilized by eIF1, dissociation of 48S complexes formed with eIF2 cou

44 renders them susceptible to dissociation by eIF1.

45 s, after which tRNA and mRNA are released by eIF1/eIF1A, Ligatin, or MCT-1/DENR.

46 ces PIC assembly, but in a manner rescued by eIF1.

47 s Gcd(-) phenotype is likewise suppressed by eIF1 overexpression or the 17-21 mutation.

48 cts of this NIP1 mutation were suppressed by eIF1 overexpression, as was the Sui(-) phenotype conferr

49 ues affected by the Saccharomyces cerevisiae eIF1 mutations are also localized.

50 Sui(-) mutations in Saccharomyces cerevisiae eIF1, which increase initiation at UUG codons, reduce in

51 implicated in the yeast multifactor complex (eIF1-eIF3-eIF5-eIF2-GTP-Met-tRNA(i)(Met)).

52 stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported i

53 stoichiometric quaternary complex containing eIF1 and the minimal segments of eIF2beta, eIF3c, and eI

54 stabilize the multifactor complex containing eIF1, eIF3, eIF5, and TC, showing that eIF1 promotes PIC

55 a 43S preinitiation complex (PIC) containing eIF1 and a ternary complex (TC) of GTP-bound eIF2 and Me

56 Eukaryotic initiation factor (eIF) eIF1 maintains the fidelity of initiation codon selectio

57 were identified previously, including eIF1A, eIF1, eIF2, and eIF5.

58 titution that should strengthen the eIF2beta:eIF1 interface has the opposite genetic and biochemical

59 eIF2, eIF3, eIF1 and eIF1A promote efficient 48S initiation complex

60 The presence of eIF2, eIF3, eIF1, eIF1A, and Met-tRNAi(Met) was sufficient for recyc

61 can be mediated by initiation factors eIF3, eIF1, and eIF1A, this energy-free mechanism can function

62 don and report that initiation factors eIF3, eIF1, eIF1A, and eIF3j, a loosely associated subunit of

63 initiation factors in vitro, including eIF3, eIF1, eIF5, and eIF1A.

64 The TC, eIF3, eIF1, and eIF1A cooperatively bind to the 40S subunit, y

65 In cooperation with eIF3, eIF1, and eIF1A, Met-tRNA(Met)(i)/eIF2/GTP binds to 40S

66 including Pdcd4-40S and Pdcd4-40S-eIF4A-eIF3-eIF1 complexes.

67 et) ternary complex (TC) interacts with eIF3-eIF1-eIF5 complex to form the multifactor complex (MFC),

68 rm the 40 S preinitiation complex (40 S.eIF3.eIF1.eIF1A.Met-tRNA(i).eIF2.GTP).

69 e findings suggest the occurrence of an eIF3/eIF1/eIF5/eIF2 multifactor complex, which was observed i

70 D) bridges interaction between eIF2 and eIF3/eIF1 in a multifactor complex containing Met-tRNA(i)(Met

71 (i)(Met) ternary complex (TC) binds the eIF3/eIF1/eIF5 complex to form the multifactor complex (MFC),

72 Interestingly, eIF4G1-eIF1 interaction itself is negatively regulated by ER st

73 ablished, the regulatory functions of eIF4G1-eIF1 are poorly understood.

74 , we report the identification of the eIF4G1-eIF1 inhibitors i14G1-10 and i14G1-12.

75 eIF5, eIF1 and HCR1 co-purified with this subcomplex, but not

76 f eIF2beta bind three common partners, eIF5, eIF1, and mRNA.

77 it binds to, and stabilizes, the eIF3-eIF5- eIF1-eIF2 multifactor complex and is required for the no

78 tion of a stress-inducible cDNA that encodes eIF1 suggests that modulation of translation initiation

79 in other eukaryotes, the yeast gene encoding eIF1 (SUI1) contains an AUG in poor context, which could

80 esidues that are identical in all eukaryotic eIF1 proteins.

81 In addition, excess eIF1 inhibits growth of a second eIF4G mutant defective

82 Interestingly, excess eIF1 carrying the sui1-1 mutation, known to relax the ac

83 Eukaryotic initiation factor eIF1 and the functional C-terminal domain of prokaryotic

84 the role of the mammalian initiation factor eIF1 in the formation of the 40 S preinitiation complex

85 we identified translation initiation factor eIF1.2 as a critical factor for T. gondii differentiatio

86 ologous to the translation initiation factor eIF1/SUI1; these proteins may comprise a novel type of t

87 he eukaryotic translation initiation factors eIF1 and eIF5.

88 show that the presence of initiation factors eIF1, eIF1A and eIF3 in the 40S preinitiation complex (4

89 Two eukaryotic initiation factors, eIF1 and eIF1A, are key actors in this process.

90 s involves the binding of two small factors, eIF1 and eIF1A, to the small (40S) ribosomal subunit.

91 Nevertheless, both forms of FLAG-eIF1 fail to bind eIF3 and are incorporated into the 43

92 Furthermore, N-terminal FLAG-eIF1 overexpression reduces eIF2 binding to the ribosome

93 is lethal; overexpression of C-terminal FLAG-eIF1 severely impedes 43 S complex formation and derepre

94 Following eIF1 dissociation, the N-terminal domain of eIF5 fails t

95 llowing cellular stress, decreased following eIF1 overexpression and was eIF4A and M7G cap-dependent.

96 hese studies suggest that it is possible for eIF1 and eIF1A to bind the 40 S preinitiation complex pr

97 ic/acidic boxes), that the binding sites for eIF1 and eIF3c are located in a conserved surface region

98 odon selection during 48S complex formation, eIF1 also participates in maintaining the fidelity of th

99 This interaction explains how eIF1 is recruited to the 40S ribosomal subunit.

100 To understand how eIF1 plays its discriminatory role, we determined its po

101 Human eIF1 and eIF1A bind cooperatively to the 40 S subunit, r

102 e determined the solution structure of human eIF1 with an N-terminal His tag using NMR spectroscopy.

103 partial sequence of recently purified human eIF1.

104 We also show that like IF3, eIF1 can influence initiator tRNA selection, which occur

105 by an eIF1A mutation (17-21) known to impede eIF1 dissociation in vitro.

106 omplex revealed several basic amino acids in eIF1 contacting 18 S rRNA, and we tested the prediction

107 A F97L mutation in eIF1.2 or the genetic ablation of eIF1.2 (Deltaeif1.2) m

108 at the SUI1 AUG, whereas Ssu(-) mutations in eIF1 and eIF1A decrease SUI1 expression with the native,

109 We also describe Gcd(-) mutations in eIF1 that impair TC loading on 40S subunits or destabili

110 ion (Sui(-) phenotype) by allowing increased eIF1 release at non-AUG codons.

111 We find that increased eIF1-40S ribosome interaction during mitosis is mediated

112 Interestingly, eIF1-KH includes the altered hydrophobic residues.

113 nslatome analyses revealed that i14G1s mimic eIF1 and eIF4G1 perturbations on the stringency of start

114 eIF1A enhances the ability of eIF1 to dissociate aberrantly assembled complexes from m

115 utation in eIF1.2 or the genetic ablation of eIF1.2 (Deltaeif1.2) markedly impeded bradyzoite cyst fo

116 is process and report that in the absence of eIF1 and DHX29, eIFs 4A, 4B and 4G promote efficient byp

117 In the absence of eIF1, 43S complexes could no longer discriminate between

118 In the absence of eIF1, eIF5-stimulated hydrolysis of eIF2-bound GTP occur

119 eIF3 dramatically increases the affinity of eIF1 and eIF3j for the 40 S subunit.

120 uitment of TC also increases the affinity of eIF1 for the 40 S subunit, but this interaction has an i

121 py to systematically measure the affinity of eIF1, eIF1A, and eIF3j in the presence of different comb

122 mplexes with a hyperstoichiometric amount of eIF1.

123 The stable association of eIF1 with 40 S subunits required the presence of eIF3.

124 in multiple segments reduced the binding of eIF1 or eIF5 to the NIP1-NTD.

125 Together, our data indicate that binding of eIF1 to the c/Nip1-NTD is equally important for its init

126 e also show that eIF5 antagonizes binding of eIF1 to the complex and that key interactions of eIF1 wi

127 Mutations that weaken binding of eIF1 to the PIC decrease the fidelity of start codon rec

128 ween the binding of eIF3j and the binding of eIF1, eIF1A, and TC with the 40 S subunit.

129 se findings indicate that direct contacts of eIF1 with 18 S rRNA seen in the Tetrahymena 40 S.eIF1 co

130 However, the contributions of eIF1, eIF1A, eIF3, and the eIF2-GTP-Met-tRNAi ternary co

131 that AUG recognition evokes dissociation of eIF1 from its 40S binding site, ejection of the eIF1A-CT

132 codon is thought to require dissociation of eIF1 from the 40 S ribosomal subunit, enabling irreversi

133 rrests scanning and promotes dissociation of eIF1 from the 40S subunit.

134 this movement is coupled to dissociation of eIF1 from the PIC, a critical event in start codon recog

135 Dissociation of eIF1 from the preinitiation complex (PIC) allows release

136 trolled by the AUG-dependent dissociation of eIF1 from the preinitiation complex.

137 in gating phosphate release, dissociation of eIF1 triggers conversion from an open, scanning-competen

138 Although the ribosome-binding face of eIF1 was identified, interfaces to other preinitiation c

139 tiation at UUG codons, reduce interaction of eIF1 with 40S subunits in vitro and in vivo, and both de

140 to the complex and that key interactions of eIF1 with its partners are modulated by the charge at an

141 These structures reveal the locations of eIF1, eIF1A, mRNA and initiator transfer RNA bound to th

142 very favorable for an indirect mechanism of eIF1's action by influencing the conformation of the pla

143 reduced approximately 5-fold on omission of eIF1 and eIF1A.

144 By contrast, overexpression of eIF1 exacerbated the tif5-7A phenotype because eIF1 form

145 In vivo, co-overexpression of eIF1 or eIF5 reverses the genetic suppression of an eIF4

146 Overexpression of eIF1, which is thought to monitor codon-anticodon intera

147 A mutation altering the basic part of eIF1-KH is lethal and shows a dominant phenotype indicat

148 xcellent candidate for the direct partner of eIF1-KH that mediates the critical link.

149 Selectively depleting the nuclear pool of eIF1 eliminates the change to translational stringency d

150 mediated by the release of a nuclear pool of eIF1 upon nuclear envelope breakdown.

151 The position of eIF1 on the 40S subunit suggests that although eIF1 is u

152 Unexpectedly, the position of eIF1 on the 40S subunit was strikingly similar to the po

153 lated region (5'-UTR) and in the presence of eIF1 scan along it and locate the initiation codon witho

154 -) phenotypes without increasing the rate of eIF1 release.

155 propose that the coordinated recruitment of eIF1 to the 40 S ribosome in the MFC is critical for the

156 ons that eIF3 is required for recruitment of eIF1 to the small ribosomal subunit.

157 Our results also suggest that release of eIF1 from the PIC and movement of the CTT of eIF1A are t

158 ts in a conformational change and release of eIF1 from the ribosome.

159 d assists the start codon-induced release of eIF1, the major antagonist of establishing tRNA(i)(Met):

160 ined mutations at the penultimate residue of eIF1, G107, that produce Sui(-) phenotypes without incre

161 at the alteration of hydrophobic residues of eIF1 disrupts a critical link to the preinitiation compl

162 rt codon selection and the opposing roles of eIF1-eIF4G1 in scanning-dependent and scanning-independe

163 l tail of eIF1A, changes in the structure of eIF1 likely instrumental in its subsequent release, and

164 ethered to seven positions on the surface of eIF1 places eIF1 on the interface surface of the platfor

165 Here we show that FLAG epitope tagging of eIF1 at either terminus abolishes its in vitro interacti

166 C-terminal FLAG tagging of eIF1 is lethal; overexpression of C-terminal FLAG-eIF1 s

167 mplicate the unstructured N-terminal tail of eIF1 in blocking rearrangement to the closed conformatio

168 One domain has the fold similar to that of eIF1, which is crucial for the scanning and initiation c

169 o retrograde scanning, strongly dependent on eIF1 and eIF1A.

170 is induction of AIRAP is solely dependent on eIF1 and the uORF kozak context.

171 of the nuclear membrane at mitosis.(1) Only eIF1 appears to be involved in this regulation, and its

172 eIF2beta or eIF1 substitutions disrupting these contacts increase in

173 s led to release of eIF2-GDP but not eIF3 or eIF1.

174 y of start codon selection by overexpressing eIF1 or eIF5 modulates the expression of Hox reporters.

175 one deacetylase 2B but did not phosphorylate eIF1, eIF1A, eIF4A, eIF4E, eIF4G, eIFiso4E, or eIFiso4G.

176 even positions on the surface of eIF1 places eIF1 on the interface surface of the platform of the 40S

177 yeast eIF1 are required to prevent premature eIF1 dissociation from scanning ribosomes at non-AUG tri

178 and mammals, this mechanism does not prevent eIF1 overproduction in yeast, accounting for the hyperac

179 ay facilitate eIF5 association by preventing eIF1 rebinding to 48S PIC.

180 Previously, eIF1 mutations were identified that increase initiation

181 YciH, a prokaryotic eIF1 homologue, could perform some of IF3's functions, w

182 poor context of the eIF1 AUG codon to reduce eIF1 abundance.

183 codon base-pairing in 48S complexes relieved eIF1's inhibition.

184 es not involve scanning and does not require eIF1, eIF1A, and the eIF4E subunit of eIF4F.

185 rnary complex to 40 S subunits also required eIF1.

186 The resulting complex requires eIF1, eIF1A, eIF4A, eIF4B and eIF4F to bind to a messeng

187 rough dVI to the initiation codon, requiring eIF1 to bypass its AUG.

188 with 18 S rRNA seen in the Tetrahymena 40 S.eIF1 complex are crucial in yeast to stabilize the open

189 The crystal structure of a Tetrahymena 40 S.eIF1 complex revealed several basic amino acids in eIF1

190 hat in addition to its function in scanning, eIF1 also plays a principal role in initiation codon sel

191 Although eIF1 and eIF1A promote scanning, eIF1 and possibly the C-terminal tail of eIF1A must be d

192 the key regulator of start-codon selection, eIF1.

193 Overexpressing the NIP1-NTD sequestered eIF1-eIF5-eIF2 in a defective subcomplex that derepresse

194 (PIC) containing the 40S ribosomal subunit, eIF1, eIF1A, eIF3, ternary complex (eIF2-GTP-Met-tRNAi),

195 to the preinitiation complex that suppresses eIF1 release before start codon selection.

196 These findings demonstrate that eIF1 dissociation is a critical step in start codon sele

197 ults provide the first in vivo evidence that eIF1 plays an important role in promoting 43 S complex f

198 We hypothesize that eIF1 acts by antagonizing conformational changes that oc

199 The data further indicate that eIF1 dissociation must be accompanied by the movement of

200 Our data indicate that eIF1 plays multiple roles in start codon recognition and

201 This indicates that eIF1 and eIF1A communicate with one another when bound t

202 Here we report that eIF1 and eIF1A are also both essential for translation i

203 NMR, but GST pull-down experiments show that eIF1 binds specifically to the p110 subunit of eIF3.

204 We show that eIF1 is phosphorylated under specific conditions that in

205 ining eIF1, eIF3, eIF5, and TC, showing that eIF1 promotes PIC assembly in vivo beyond its important

206 Our results suggest that eIF1 and eIF1A promote an open, scanning-competent prein

207 Together, our findings suggest that eIF1.2 functions by regulating the translation of key di

208 These results support that eIF1 functions in ensuring the fidelity of AUG start cod

209 It is thought that eIF1 prevents recognition of non-AUGs by promoting scann

210 The eIF1 Sui(-) mutations also derepress translation of GCN4

211 ressed the Sui(-) phenotypes produced by the eIF1-D83G and eIF5-G31R mutations.

212 t suppresses Sui(-) mutations) decreases the eIF1 off-rate.

213 eps in translation initiation, including the eIF1- and eIF1A-dependent delivery of initiator methiony

214 acerbating the effect of poor context of the eIF1 AUG codon to reduce eIF1 abundance.

215 ic and biochemical studies indicate that the eIF1 N-terminal tail plays a stimulatory role in coopera

216 nstrated, at single-molecule level, that the eIF1.2 F97L mutation impacts the scanning process of the

217 racy of initiation codon selection belong to eIF1 and eIF1A, whereas the mammalian-specific DHX29 hel

218 Nip1 subunit, which mediates eIF3 binding to eIF1 and eIF5, to semirandom mutagenesis to investigate

219 that the binding of the eIF4G HEAT domain to eIF1 and eIF5 is important for maintaining the integrity

220 /eIF3- and eIF5B/eIF3-mediated mechanisms to eIF1-induced destabilization.

221 th initiator tRNA in the PIN state, prior to eIF1 release.

222 on complex components and their relevance to eIF1 function have not been determined.

223 These structures reveal that together, eIF1 and eIF1A stabilize a conformational change that op

224 AUG recognition triggers eIF1 release and rearrangement from an open PIC conforma

225 al domain of eIF5 fails to occupy the vacant eIF1 position, and eIF2beta becomes flexible.

226 P hydrolysis in 43S complexes assembled with eIF1 was much slower than in 43S or 48S complexes assemb

227 Cryo-EM models reveal eIF2beta contacts with eIF1 and Met-tRNAi exclusive to the open complex that sh

228 bunits, eliminating functional coupling with eIF1.

229 (NTD) of NIP1/eIF3c interacts directly with eIF1 and eIF5 and indirectly through eIF5 with the eIF2-

230 its C-terminal HEAT domain to interact with eIF1, eIF2, and eIF3 in the multifactor complex and with

231 (NIP1-NTD and TIF32-CTD) that interact with eIF1, eIF5, and the eIF2/GTP/Met-tRNA(i)(Met) ternary co

232 2-mediated increase in eIF5 interaction with eIF1 and eIF3c in pulldown assays and reduces the eIF5-m

233 tic initiation factor (eIF) 5 interacts with eIF1, eIF2beta, and eIF3c, thereby mediating formation o

234 eIF3) forms a multifactor complex (MFC) with eIF1, eIF2, and eIF5 that stimulates Met-tRNA(i)(Met) bi

235 ractions of NIP1 with PRT1 and of TIF32 with eIF1.

236 an in 43S or 48S complexes assembled without eIF1.

237 Yeast eIF1 inhibits initiation at non-AUG triplets, but it was

238 prediction that their counterparts in yeast eIF1 are required to prevent premature eIF1 dissociation

239 eta-hairpin loop-1, impairs binding of yeast eIF1 to 40 S.eIF1A complexes in vitro, and it confers in

240 Exploiting the solution structure of yeast eIF1, here we locate the binding site for eIF5 in its N-