Eukaryotic translation initiation (Homo sapiens)
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Description
Initiation of translation in the majority of eukaryotic cellular mRNAs depends on the 5'-cap (m7GpppN) and involves ribosomal scanning of the 5' untranslated region (5'-UTR) for an initiating AUG start codon. Therefore, this mechanism is often called cap-dependent translation initiation. Proximity to the cap, as well as the nucleotides surrounding an AUG codon, influence the efficiency of the start site recognition during the scanning process. However, if the recognition site is poor enough, scanning ribosomal subunits will ignore and skip potential starting AUGs, a phenomenon called leaky scanning. Leaky scanning allows a single mRNA to encode several proteins that differ in their amino-termini. Several eukaryotic cell and viral mRNAs initiate translation by an alternative mechanism that involves internal initiation rather than ribosomal scanning. These mRNAs contain complex nucleotide sequences, called internal ribosomal entry sites, where ribosomes bind in a cap-independent manner and start translation at the closest downstream AUG codon.
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Bibliography
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- Pause A, Belsham GJ, Gingras AC, Donzé O, Lin TA, Lawrence JC, Sonenberg N.; ''Insulin-dependent stimulation of protein synthesis by phosphorylation of a regulator of 5'-cap function.''; PubMed Europe PMC Scholia
- Sampath P, Mazumder B, Seshadri V, Fox PL.; ''Transcript-selective translational silencing by gamma interferon is directed by a novel structural element in the ceruloplasmin mRNA 3' untranslated region.''; PubMed Europe PMC Scholia
- Pestova TV, Borukhov SI, Hellen CU.; ''Eukaryotic ribosomes require initiation factors 1 and 1A to locate initiation codons.''; PubMed Europe PMC Scholia
- Mazumder B, Sampath P, Seshadri V, Maitra RK, DiCorleto PE, Fox PL.; ''Regulated release of L13a from the 60S ribosomal subunit as a mechanism of transcript-specific translational control.''; PubMed Europe PMC Scholia
- Grifo JA, Tahara SM, Morgan MA, Shatkin AJ, Merrick WC.; ''New initiation factor activity required for globin mRNA translation.''; PubMed Europe PMC Scholia
- Safer B, Adams SL, Anderson WF, Merrick WC.; ''Binding of MET-TRNAf and GTP to homogeneous initiation factor MP.''; PubMed Europe PMC Scholia
- Pestova TV, Shatsky IN, Hellen CU.; ''Functional dissection of eukaryotic initiation factor 4F: the 4A subunit and the central domain of the 4G subunit are sufficient to mediate internal entry of 43S preinitiation complexes.''; PubMed Europe PMC Scholia
- Merrick WC.; ''Eukaryotic protein synthesis: still a mystery.''; PubMed Europe PMC Scholia
- Kozak M.; ''Evaluation of the "scanning model" for initiation of protein synthesis in eucaryotes.''; PubMed Europe PMC Scholia
- Chakrabarti A, Maitra U.; ''Function of eukaryotic initiation factor 5 in the formation of an 80 S ribosomal polypeptide chain initiation complex.''; PubMed Europe PMC Scholia
- Trachsel H, Erni B, Schreier MH, Staehelin T.; ''Initiation of mammalian protein synthesis. II. The assembly of the initiation complex with purified initiation factors.''; PubMed Europe PMC Scholia
- Rowlands AG, Panniers R, Henshaw EC.; ''The catalytic mechanism of guanine nucleotide exchange factor action and competitive inhibition by phosphorylated eukaryotic initiation factor 2.''; PubMed Europe PMC Scholia
- Iost I, Dreyfus M, Linder P.; ''Ded1p, a DEAD-box protein required for translation initiation in Saccharomyces cerevisiae, is an RNA helicase.''; PubMed Europe PMC Scholia
- Benne R, Hershey JW.; ''The mechanism of action of protein synthesis initiation factors from rabbit reticulocytes.''; PubMed Europe PMC Scholia
- Schreier MH, Erni B, Staehelin T.; ''Initiation of mammalian protein synthesis. I. Purification and characterization of seven initiation factors.''; PubMed Europe PMC Scholia
- Sonenberg N, Rupprecht KM, Hecht SM, Shatkin AJ.; ''Eukaryotic mRNA cap binding protein: purification by affinity chromatography on sepharose-coupled m7GDP.''; PubMed Europe PMC Scholia
- Dever TE, Wei CL, Benkowski LA, Browning K, Merrick WC, Hershey JW.; ''Determination of the amino acid sequence of rabbit, human, and wheat germ protein synthesis factor eIF-4C by cloning and chemical sequencing.''; PubMed Europe PMC Scholia
- Merrick WC, Kemper WM, Anderson WF.; ''Purification and characterization of homogeneous initiation factor M2A from rabbit reticulocytes.''; PubMed Europe PMC Scholia
- Asano K, Clayton J, Shalev A, Hinnebusch AG.; ''A multifactor complex of eukaryotic initiation factors, eIF1, eIF2, eIF3, eIF5, and initiator tRNA(Met) is an important translation initiation intermediate in vivo.''; PubMed Europe PMC Scholia
- Peterson DT, Merrick WC, Safer B.; ''Binding and release of radiolabeled eukaryotic initiation factors 2 and 3 during 80 S initiation complex formation.''; PubMed Europe PMC Scholia
- Goumans H, Thomas A, Verhoeven A, Voorma HO, Benne R.; ''The role of eIF-4C in protein synthesis initiation complex formation.''; PubMed Europe PMC Scholia
- Imataka H, Gradi A, Sonenberg N.; ''A newly identified N-terminal amino acid sequence of human eIF4G binds poly(A)-binding protein and functions in poly(A)-dependent translation.''; PubMed Europe PMC Scholia
- Chuang RY, Weaver PL, Liu Z, Chang TH.; ''Requirement of the DEAD-Box protein ded1p for messenger RNA translation.''; PubMed Europe PMC Scholia
- Lahn BT, Page DC.; ''Functional coherence of the human Y chromosome.''; PubMed Europe PMC Scholia
- Yoder-Hill J, Pause A, Sonenberg N, Merrick WC.; ''The p46 subunit of eukaryotic initiation factor (eIF)-4F exchanges with eIF-4A.''; PubMed Europe PMC Scholia
- Pestova TV, Lomakin IB, Lee JH, Choi SK, Dever TE, Hellen CU.; ''The joining of ribosomal subunits in eukaryotes requires eIF5B.''; PubMed Europe PMC Scholia
- Damoc E, Fraser CS, Zhou M, Videler H, Mayeur GL, Hershey JW, Doudna JA, Robinson CV, Leary JA.; ''Structural characterization of the human eukaryotic initiation factor 3 protein complex by mass spectrometry.''; PubMed Europe PMC Scholia
- Majumdar R, Bandyopadhyay A, Maitra U.; ''Mammalian translation initiation factor eIF1 functions with eIF1A and eIF3 in the formation of a stable 40 S preinitiation complex.''; PubMed Europe PMC Scholia
- Dholakia JN, Wahba AJ.; ''Mechanism of the nucleotide exchange reaction in eukaryotic polypeptide chain initiation. Characterization of the guanine nucleotide exchange factor as a GTP-binding protein.''; PubMed Europe PMC Scholia
History
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External references
DataNodes
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Name | Type | Database reference | Comment |
---|---|---|---|
40S ribosomal
complex | Complex | REACT_5094 (Reactome) | |
40S:Met-tRNAi:
mRNA | Complex | REACT_3073 (Reactome) | |
40S:eIF3:eIF1A | Complex | REACT_2456 (Reactome) | |
43S complex | Complex | REACT_3677 (Reactome) | |
43S: Ceruloplasmin
mRNA:eIF4F:eIF4B: eIF4H:PABP | Complex | REACT_3267 (Reactome) | |
43S:mRNA:eIF4F:
eIF4B:eIF4H | Complex | REACT_4439 (Reactome) | |
48S complex | Complex | REACT_5152 (Reactome) | |
4E-BP | Protein | Q13541 (UniProt) | |
60S ribosomal
complex | Complex | REACT_2629 (Reactome) | |
60S ribosomal
protein L13a | Protein | P40429 (UniProt) | |
60s ribosomal
complex lacking L13a subunit | Complex | REACT_4690 (Reactome) | |
80S ribosome | Complex | REACT_4330 (Reactome) | |
80S:Met-tRNAi:
mRNA | Complex | REACT_4537 (Reactome) | |
80S:Met-tRNAi:
mRNA:eIF5B:GTP | Complex | REACT_2486 (Reactome) | |
ADP | Metabolite | 16761 (ChEBI) | |
ATP | Metabolite | 15422 (ChEBI) | |
Ceruloplasmin
mRNA:eIF4F:eIF4B: eIF4H | Complex | REACT_2288 (Reactome) | |
GDP | Metabolite | 17552 (ChEBI) | |
GTP | Metabolite | 15996 (ChEBI) | |
L13a
kinase | Unknown | REACT_6440 (Reactome) | |
Met-tRNAi | Unknown | REACT_4829 (Reactome) | |
Orthophosphate | Metabolite | 18367 (ChEBI) | |
PABP | Protein | P11940 (UniProt) | |
RNA-binding protein
in RNP (ribonucleoprotein) complexes | Unknown | REACT_3670 (Reactome) | |
eIF1 | Unknown | REACT_3030 (Reactome) | |
eIF1A | Protein | P47813 (UniProt) | |
eIF2 subunit
complex | Complex | REACT_5135 (Reactome) | |
eIF2:GDP | Complex | REACT_2996 (Reactome) | |
eIF2:GDP: eIF2B | Complex | REACT_3553 (Reactome) | |
eIF2:GTP | Complex | REACT_3909 (Reactome) | |
eIF2B subunits
complex | Complex | REACT_3897 (Reactome) | |
eIF3 subunits
complex | Complex | REACT_4891 (Reactome) | |
eIF4A subunits
complex | Complex | REACT_5786 (Reactome) | |
eIF4B | Protein | P23588 (UniProt) | |
eIF4E | Protein | P06730 (UniProt) | |
eIF4E:4E-BP | Complex | REACT_3978 (Reactome) | |
eIF4F | Complex | REACT_4441 (Reactome) | |
eIF4F:mRNP | Complex | REACT_4731 (Reactome) | |
eIF4G | Protein | Q04637 (UniProt) | |
eIF4H | Protein | Q15056 (UniProt) | |
eIF5 | Protein | P55010 (UniProt) | |
eIF5B:GDP | Complex | REACT_4697 (Reactome) | |
eIF5B:GTP | Complex | REACT_3457 (Reactome) | |
mRNA:eIF4F:eIF4B:
eIF4H | Complex | REACT_2596 (Reactome) | |
mRNP | Complex | REACT_3493 (Reactome) | |
phospho-L13a
60S ribosomal protein | Protein | P40429 (UniProt) | |
phospho-L13a
associated wth the 3' UTR GAIT element of ceruloplasmin mRNA within the translation initiation complex | Complex | REACT_5151 (Reactome) | |
ternary complex | Complex | REACT_4168 (Reactome) |
Annotated Interactions
No annotated interactions