Canonical mRNA translation in eukaryotes begins with the formation of the 43S pre-initiation complex (PIC). Its assembly requires binding of initiator Met-tRNAiMet and several eukaryotic initiation factors (eIFs) to the small ribosomal subunit (40S). Compared to their mammalian hosts, trypanosomatids present significant structural differences in their 40S, suggesting substantial variability in translation initiation. Here, we determine the structure of the 43S PIC from Trypanosoma cruzi, the parasite causing Chagas disease. Our structure shows numerous specific features, such as the variant eIF3 structure and its unique interactions with the large rRNA expansion segments (ESs) 9S, 7S, and 6S, and the association of a kinetoplastid-specific DDX60-like helicase. It also reveals the 40S-binding site of the eIF5 C-terminal domain and structures of key terminal tails of several conserved eIFs underlying their activities within the PIC. Our results are corroborated by glutathione S-transferase (GST) pull-down assays in both human and T. cruzi and mass spectrometry data.
- MeSH
- Models, Molecular MeSH
- Protein Biosynthesis immunology MeSH
- Mammals MeSH
- Trypanosomatina pathogenicity MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
One of the key roles of the 12-subunit eukaryotic translation initiation factor 3 (eIF3) is to promote the formation of the 43S and 48S pre-initiation complexes (PICs). However, particular contributions of its individual subunits to these two critical initiation reactions remained obscure. Here, we adapted formaldehyde gradient cross-linking protocol to translation studies and investigated the efficiency of the 43S and 48S PIC assembly in knockdowns of individual subunits of human eIF3 known to produce various partial subcomplexes. We revealed that eIF3d constitutes an important intermolecular bridge between eIF3 and the 40S subunit as its elimination from the eIF3 holocomplex severely compromised the 43S PIC assembly. Similarly, subunits eIF3a, c and e were found to represent an important binding force driving eIF3 binding to the 40S subunit. In addition, we demonstrated that eIF3c, and eIF3k and l subunits alter the efficiency of mRNA recruitment to 43S PICs in an opposite manner. Whereas the eIF3c knockdown reduces it, downregulation of eIF3k or eIF3l increases mRNA recruitment, suggesting that the latter subunits possess a regulatory potential. Altogether this study provides new insights into the role of human eIF3 in the initial assembly steps of the translational machinery.
- MeSH
- Eukaryotic Initiation Factor-3 genetics MeSH
- Formaldehyde pharmacology MeSH
- Humans MeSH
- Ribosome Subunits, Small, Eukaryotic genetics MeSH
- RNA, Messenger genetics MeSH
- Microtubule-Associated Proteins genetics MeSH
- Protein Biosynthesis genetics MeSH
- Cross-Linking Reagents pharmacology MeSH
- Ribosomes genetics MeSH
- Protein Binding MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
... rowth of Vi ruses 3 9 -- The Virus Replication Cycle 41 -- Attachment 42 -- Penetration and Uncoating 43 ... ... Lymphocytes 69 -- Cytotoxic T (Tc) Lymphocytes 69 y/ô T Lymphocytes 69 -- The Major Histocompatibility Complex ... ... Active Immunization Policy Passive Immunization The WHO Expanded Program on Immunization and Other Initiatives ... ... and Immunity 387 -- Laboratory Diagnosis 388 -- Epidemiology 388 -- Post-Exposure Prophylaxis 390 -- Pre-Exposure ... ... -- Reye\'s Syndrome 546 -- Chronic Demyelinating Diseases 546 -- HIV Encephalopathy (HIV Dementia Complex ...
Fifth edition xix, 583 stran : ilustrace ; 29 cm
... ¦tacer 10 -- INTRODUCTION TO THE CELL 1 -- Cells and Genomes 1 -- Cell Chemistry and Bioenergetics 43 ... ... -- THE CHEMICAL COMPONENTS OF A CELL 43 -- Water Is Held Together by Hydrogen Bonds 44 -- Four Types ... ... Proteins -- An Elaborate Ubiquitin-Conjugating Syster- s -sec xs % Proteins -- Protein Complexes with ... ... Proteins Are Controlled by Covalent Modifications Direct Them to Specific Sites Inside the Cel A Complex ... ... be-r Complex Connects Photosystem II to •stem I -- Carries Out the Second Charge-Separation \" *ne Z ...
Sixth edition xxxiv, 1430 stran v různém stránkování : ilustrace (převážně barevné) ; 29 cm
- MeSH
- Cells * MeSH
- Molecular Biology MeSH
- Conspectus
- Biochemie. Molekulární biologie. Biofyzika
- NML Fields
- molekulární biologie, molekulární medicína
- NML Publication type
- učebnice vysokých škol
... 16 Levels upon levels of evidence, 17 Synthesised sources: systems, summaries and syntheses, 17 Pre-appraised ... ... reports, 40 -- The traditional hierarchy of evidence, 41 A note on ethical considerations, 42 References, 43 ... ... out of a pharmaceutical representative, 86 References, 88 -- Chapter 7 Papers that report trials of complex ... ... interventions, 90 Complex interventions, 90 -- Ten questions to ask about a paper describing a complex ... ... 190 -- Ten questions to ask about a paper describing a quality improvement initiative, 193 References ...
5th ed. xxii, 261 s. : il., tab. ; 22 cm
- MeSH
- Controlled Clinical Trials as Topic MeSH
- Evidence-Based Medicine MeSH
- Publication type
- Handbook MeSH
- Conspectus
- Patologie. Klinická medicína
- NML Fields
- lékařství
Transfer of genetic information from genes into proteins is mediated by messenger RNA (mRNA) that must be first recruited to ribosomal pre-initiation complexes (PICs) by a mechanism that is still poorly understood. Recent studies showed that besides eIF4F and poly(A)-binding protein, eIF3 also plays a critical role in this process, yet the molecular mechanism of its action is unknown. We showed previously that the PCI domain of the eIF3c/NIP1 subunit of yeast eIF3 is involved in RNA binding. To assess the role of the second PCI domain of eIF3 present in eIF3a/TIF32, we performed its mutational analysis and identified a 10-Ala-substitution (Box37) that severely reduces amounts of model mRNA in the 43-48S PICs in vivo as the major, if not the only, detectable defect. Crystal structure analysis of the a/TIF32-PCI domain at 2.65-Å resolution showed that it is required for integrity of the eIF3 core and, similarly to the c/NIP1-PCI, is capable of RNA binding. The putative RNA-binding surface defined by positively charged areas contains two Box37 residues, R363 and K364. Their substitutions with alanines severely impair the mRNA recruitment step in vivo suggesting that a/TIF32-PCI represents one of the key domains ensuring stable and efficient mRNA delivery to the PICs.
- MeSH
- Alanine genetics MeSH
- Eukaryotic Initiation Factor-3 chemistry genetics metabolism MeSH
- Phenotype MeSH
- Peptide Chain Initiation, Translational * MeSH
- Ribosome Subunits, Small, Eukaryotic metabolism MeSH
- RNA, Messenger metabolism MeSH
- Models, Molecular MeSH
- Mutation MeSH
- Saccharomyces cerevisiae Proteins chemistry genetics metabolism MeSH
- Amino Acid Substitution MeSH
- Protein Structure, Tertiary MeSH
- Basic-Leucine Zipper Transcription Factors genetics MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
... discrimination between self and nonself. 11 -- 1-8 Adaptive immune responses are initiated by antigen ... ... recognize foreign antigens as peptide fragments bound to proteins of the major histocompatibility complex ... ... by activation of the C1 complex and is homologous to the lectin pathway. 55 -- 2-8 Complement activation ... ... is largely confined to the surface on which it is initiated. . 56 -- 2-9 The alternative pathway is ... ... show a similar orientation of the -- T-cell receptor over the peptide:MHC complex. 147 -- 4-17 The CD4 ...
8th ed. xix, 868 s. : il., tab.
- MeSH
- Immunity MeSH
- Immune System MeSH
- Immunotherapy MeSH
- Publication type
- Monograph MeSH
- Conspectus
- Patologie. Klinická medicína
- NML Fields
- alergologie a imunologie
- biologie
... A Special Initiator tRNA Starts the Polypeptide Chain 158 -- ??? ... ... Small Subunits Scan for Initiation Sites on Eukaryotic mRNA 162 -- ??? ... ... Eukaryotes Use a Complex of Many Initiation Factors 164 -- ??? ... ... The Synaptonemal Complex Forms after Double-Strand Breaks 467 -- ??? ... ... snRNAs Are Required for Splicing 674 U1 snRNP Initiates Splicing 676 -- ??? ...
xvii, 892 s. : il.
- MeSH
- DNA genetics MeSH
- Genetic Phenomena MeSH
- Genome MeSH
- Genes physiology MeSH
- Proteins genetics MeSH
- RNA genetics MeSH
- Publication type
- Monograph MeSH
- Conspectus
- Obecná genetika. Obecná cytogenetika. Evoluce
- NML Fields
- genetika, lékařská genetika
... 2 -- 6.3.2 Preferred sequences 339 -- 6.4 Pre-sequences 345 -- 6.4.I General remarks 345 -- 6.4.2 Pre-announcements ... ... , see under presequences pre-closings, see under pre-sequences pre-emptive use, of deictic words, 75- ... ... , see under pre-sequences presentatives, 65 pre-s, 345 ; see under pre-sequences (first turns of) pre-sequences ... ... , 355-6, 357-64 passim pre-invitations, 346-7 pre-offers, 349 pre-requests, 321, 327, 343, 344, 347, ... ... 43-5, ? ...
Cambridge textbooks of linguistics
15th ed. xvi, 420 s.
... chapter 3 Protein Structure and Function 41 -- 3.1 Proteins Are Built from a Repertoire of 20 Amino Acids 43 ... ... 11.1.3 Monosaccharides Are Joined to Alcohols and -- Amines Through Glycosidic Bonds 300 -- 11.2 Complex ... ... 11.3.2 Protein Glycosylation Takes Place in the -- Lumen of the Endoplasmic Reticulum and the Golgi Complex ... ... - Reaction Centers 543 -- 19.5.1 Resonance Energy Transfer Allows Energy to Move from the Site of Initial ... ... Synthesis 618 xxxii CONTENTS -- 22.4.4 Fatty Acids Are Synthesized by a Multifunctional -- Enzyme Complex ...
5th ed. xvii, 974 s. : il., tab., grafy ; 32 cm
