Publication Date:
2012-06-30
Description:
Effective immune surveillance by cytotoxic T cells requires newly synthesized polypeptides for presentation by major histocompatibility complex (MHC) class I molecules. These polypeptides are produced not only from conventional AUG-initiated, but also from cryptic non-AUG-initiated, reading frames by distinct translational mechanisms. Biochemical analysis of ribosomal initiation complexes at CUG versus AUG initiation codons revealed that cells use an elongator leucine-bound transfer RNA (Leu-tRNA) to initiate translation at cryptic CUG start codons. CUG/Leu-tRNA initiation was independent of the canonical initiator tRNA (AUG/Met-tRNA(i)(Met)) pathway but required expression of eukaryotic initiation factor 2A. Thus, a tRNA-based translation initiation mechanism allows non-AUG-initiated protein synthesis and supplies peptides for presentation by MHC class I molecules.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Starck, Shelley R -- Jiang, Vivian -- Pavon-Eternod, Mariana -- Prasad, Sharanya -- McCarthy, Brian -- Pan, Tao -- Shastri, Nilabh -- New York, N.Y. -- Science. 2012 Jun 29;336(6089):1719-23. doi: 10.1126/science.1220270.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22745432" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Antigen Presentation/*genetics
;
Antigen-Presenting Cells/immunology
;
COS Cells
;
Cercopithecus aethiops
;
*Codon, Initiator
;
HeLa Cells
;
Histocompatibility Antigens Class I/*genetics/*immunology
;
Humans
;
Hybridomas/immunology
;
Mice
;
Mice, Inbred C57BL
;
Mice, Transgenic
;
Peptide Chain Initiation, Translational
;
Protein Biosynthesis/*genetics
;
*RNA, Transfer, Leu
;
T-Lymphocytes/immunology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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