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1.
Gillen CM Gao Y Niehaus-Sauter MM Wylde MR Wheatly MG 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2008,150(2):170-176
Eukaryotic elongation factor 1Bγ (eEF1Bγ) is a subunit of elongation factor 1 (EF1), which regulates the recruitment of amino acyl-tRNAs to the ribosome during protein synthesis in eukaryotes. In addition to structural roles within eEF1, eEF1Bγ has properties which suggest sensory or regulatory activities. We have cloned eEF1Bγ from axial abdominal muscle of freshwater crayfish, Procambarus clarkii. The predicted amino acid sequence has 66% identity to Locusta migratoria eEF1Bγ and 65% identity to Artemia salina eEF1Bγ. We measured eEF1Bγ expression by real-time PCR, using the relative quantification method with 18s ribosomal RNA as an internal calibrator. eEF1Bγ expression was lowest in gill, axial abdominal muscle, and hepatopancreas, and was highest in the antennal gland (5.7-fold above hepatopancreas) and cardiac muscle (7.8-fold above hepatopancreas). In axial abdominal muscle, eEF1Bγ expression was 4.4-fold higher in premolt and 11.9 higher in postmolt compared to intermolt. In contrast, eEF1Bγ was decreased or unchanged in epithelial tissues during pre- and postmolt. eEF1Bγ expression in the hepatopancreas was 3.5-fold higher during intermolt compared to premolt and was unchanged in gill and antennal gland. No significant differences in eEF1Bγ were found after 1 week of acclimation to 4 °C. These results show that eEF1Bγ is regulated at the mRNA level with tissue-specific differences in expression patterns. 相似文献
2.
3.
Marco A Campinho Nádia Silva Mari A Nowell Lynda Llewellyn Glen E Sweeney Deborah M Power 《BMC developmental biology》2007,7(1):71
Background
Flatfish metamorphosis is a thyroid hormone (TH) driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in Troponin T (TnT), a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied. 相似文献4.
Carlos Infante Manuel Manchado Esther Asensio José Pedro Ca?avate 《BMC developmental biology》2007,7(1):118
Background
Keratins make up the largest subgroup of intermediate filaments, and, in chordates, represent the most abundant proteins in epithelial cells. They have been associated with a wide range of functions in the cell, but little information is still available about their expression profile and regulation during flatfish metamorphosis. Senegalese sole (Solea senegalensis) is a commercially important flatfish in which no keratin gene has been described yet. 相似文献5.
Ivana Momčilović Danijel Pantelić Snežana Zdravković-Korać Jasmina Oljača Jelena Rudić Jianming Fu 《Planta》2016,244(3):671-679
Main conclusion
Potato eukaryotic elongation factor 1A comprises multiple isoforms, some of which are heat-inducible or heat-upregulated and might be important in alleviating adverse effects of heat stress on plant productivity. Heat stress substantially reduces crop productivity worldwide, and will become more severe due to global warming. Identification of proteins involved in heat stress response may help develop varieties for heat tolerance. Eukaryotic elongation factor 1A (eEF1A) is a cytosolic, multifunctional protein that plays a central role in the elongation phase of translation. Some of the non-canonical eEF1A activities might be important in developing plant heat-stress tolerance. In this study, we investigated effects of heat stress (HS) on eEF1A expression at the protein level in potato, a highly heat vulnerable crop. Our results from both the controlled environment and the field have shown that potato eEF1A is a heat-inducible protein of 49.2-kDa with multiple isoforms (5–8). Increase in eEF1A abundance under HS can be mainly attributed to 2–3 basic polypeptides/isoforms. A significant correlation between eEF1A abundance and the potato productivity in the field was observed in two extremely hot years 2011 and 2012. Genomic Southern blot analysis indicated the existence of multiple genes encoding eEF1A in potato. Identification, isolation and utilization of heat-inducible eEF1A genes might be helpful for the development of the heat-tolerant varieties.6.
Xuan Chen Long He Miaoze Xu Jin Yang Juan Li Tianye Zhang Qiansheng Liao Hengmu Zhang Jian Yang Jianping Chen 《Molecular Plant Pathology》2021,22(11):1383-1398
The Chinese wheat mosaic virus (CWMV) genome consists of two positive-strand RNAs that are required for CWMV replication and translation. The eukaryotic translation elongation factor (eEF1A) is crucial for the elongation of protein translation in eukaryotes. Here, we show that silencing eEF1A expression in Nicotiana benthamiana plants by performing virus-induced gene silencing can greatly reduce the accumulation of CWMV genomic RNAs, whereas overexpression of eEF1A in plants increases the accumulation of CWMV genomic RNAs. In vivo and in vitro assays showed that eEF1A does not interact with CWMV RNA-dependent RNA polymerase. Electrophoretic mobility shift assays revealed that eEF1A can specifically bind to the 3ʹ-untranslated region (UTR) of CWMV genomic RNAs. By performing mutational analyses, we determined that the conserved region in the 3ʹ-UTR of CWMV genomic RNAs is necessary for CWMV replication and translation, and that the sixth stem-loop (SL-6) in the 3ʹ-UTR of CWMV genomic RNAs plays a key role in CWMV infection. We conclude that eEF1A is an essential host factor for CWMV infection. This finding should help us to develop new strategies for managing CWMV infections in host plants. 相似文献
7.
Dinesh C. Soares Paul N. Barlow Helen J. Newbery David J. Porteous Catherine M. Abbott 《PloS one》2009,4(7)
Background
Despite sharing 92% sequence identity, paralogous human translation elongation factor 1 alpha-1 (eEF1A1) and elongation factor 1 alpha-2 (eEF1A2) have different but overlapping functional profiles. This may reflect the differential requirements of the cell-types in which they are expressed and is consistent with complex roles for these proteins that extend beyond delivery of tRNA to the ribosome.Methodology/Principal Findings
To investigate the structural basis of these functional differences, we created and validated comparative three-dimensional (3-D) models of eEF1A1 and eEF1A2 on the basis of the crystal structure of homologous eEF1A from yeast. The spatial location of amino acid residues that vary between the two proteins was thereby pinpointed, and their surface electrostatic and lipophilic properties were compared. None of the variations amongst buried amino acid residues are judged likely to have a major structural effect on the protein fold, or to affect domain-domain interactions. Nearly all the variant surface-exposed amino acid residues lie on one face of the protein, in two proximal but distinct sub-clusters. The result of previously performed mutagenesis in yeast may be interpreted as confirming the importance of one of these clusters in actin-bundling and filament disorganization. Interestingly, some variant residues lie in close proximity to, and in a few cases show differences in interactions with, residues previously inferred to be directly involved in binding GTP/GDP, eEF1Bα and aminoacyl-tRNA. Additional sequence-based predictions, in conjunction with the 3-D models, reveal likely differences in phosphorylation sites that could reconcile some of the functional differences between the two proteins.Conclusions
The revelation and putative functional assignment of two distinct sub-clusters on the surface of the protein models should enable rational site-directed mutagenesis, including homologous reverse-substitution experiments, to map surface binding patches onto these proteins. The predicted variant-specific phosphorylation sites also provide a basis for experimental verification by mutagenesis. The models provide a structural framework for interpretation of the resulting functional analysis. 相似文献8.
Apart from its canonical function in translation elongation, eukaryotic translation elongation factor 1A (eEF1A) has been shown to interact with the actin cytoskeleton. Amino acid substitutions in eEF1A that reduce its ability to bind and bundle actin in vitro cause improper actin organization in vivo and reduce total translation. Initial in vivo analysis indicated the reduced translation was through initiation. The mutant strains exhibit increased levels of phosphorylated initiation factor 2α (eIF2α) dependent on the presence of the general control nonderepressible 2 (Gcn2p) protein kinase. Gcn2p causes down-regulation of total protein synthesis at initiation in response to increases in deacylated tRNA levels in the cell. Increased levels of eIF2α phosphorylation are not due to a general reduction in translation elongation as eEF2 and eEF3 mutants do not exhibit this effect. Deletion of GCN2 from the eEF1A actin bundling mutant strains revealed a second defect in translation. The eEF1A actin-bundling proteins exhibit changes in their elongation activity at the level of aminoacyl-tRNA binding in vitro. These findings implicate eEF1A in a feedback mechanism for regulating translation at initiation. 相似文献
9.
10.
Dmitry S Kanibolotsky Oleksandra V Novosyl'na Catherine M Abbott Boris S Negrutskii Anna V El'skaya 《BMC structural biology》2008,8(1):1-16
Background
Eukaryotic translation elongation factor eEF1A directs the correct aminoacyl-tRNA to ribosomal A-site. In addition, eEF1A is involved in carcinogenesis and apoptosis and can interact with large number of non-translational ligands. There are two isoforms of eEF1A, which are 98% similar. Despite the strong similarity, the isoforms differ in some properties. Importantly, the appearance of eEF1A2 in tissues in which the variant is not normally expressed can be coupled to cancer development. We reasoned that the background for the functional difference of eEF1A1 and eEF1A2 might lie in changes of dynamics of the isoforms.Results
It has been determined by multiple MD simulation that eEF1A1 shows increased reciprocal flexibility of structural domains I and II and less average distance between the domains, while increased non-correlated diffusive atom motions within protein domains characterize eEF1A2. The divergence in the dynamic properties of eEF1A1 and eEF1A2 is caused by interactions of amino acid residues that differ between the two variants with neighboring residues and water environment. The main correlated motion of both protein isoforms is the change in proximity of domains I and II which can lead to disappearance of the gap between the domains and transition of the protein into a "closed" conformation. Such a transition is reversible and the protein can adopt an "open" conformation again. This finding is in line with our earlier experimental observation that the transition between "open" and "closed" conformations of eEF1A could be essential for binding of tRNA and/or other biological ligands. The putative calmodulin-binding region Asn311-Gly327 is less flexible in eEF1A1 implying its increased affinity for calmodulin. The ability of eEF1A1 rather than eEF1A2 to interact with Ca2+/calmodulin is shown experimentally in an ELISA-based test.Conclusion
We have found that reversible transitions between "open" and "close" conformations of eEF1A provide a molecular background for the earlier observation that the eEF1A molecule is able to change the shape upon interaction with tRNA. The ability of eEF1A1 rather than eEF1A2 to interact with calmodulin is predicted by MD analysis and showed experimentally. The differential ability of the eEF1A isoforms to interact with signaling molecules discovered in this study could be associated with cancer-related properties of eEF1A2. 相似文献11.
Meizhi Niu Manuela Klingler-Hoffmann Julie A Brazzatti Briony Forbes Chareeporn Akekawatchai Peter Hoffmann Shaun R McColl 《Proteome science》2013,11(1):1-12
Background
Cancer cell migration is fundamentally required for breast tumour invasion and metastasis. The insulin-like growth factor 1 tyrosine kinase receptor (IGF-1R) and the chemokine G-protein coupled receptor, CXCR4 have been shown to play an important role in breast cancer metastasis. Our previous study has shown that IGF-1R can transactivate CXCR4 via a physical association in the human MDA-MB-231 metastatic breast cancer cell line and that this plays a key role in IGF-I-induced migration of these cells. In the present study we used pharmacological inhibition and RNAi to identify PI3Kγ as an important migration signalling molecule downstream of receptor transactivation in MDA-MB-231 cells. To identify PI3Kγ-regulated proteins upon transactivation of CXCR4 by IGF-I, we undertook a comparative proteomics approach using 2-D- Fluorescence Difference Gel Electrophoresis (DIGE) and identified the proteins by mass spectrometry.Results
These experiments identified eukaryotic elongation factor 2 (eEF2) as a novel downstream target of PI3Kγ after activation of the IGF-1R-CXCR4 heterodimer by IGF-I. Further analysis demonstrated that eEF2 is phosphorylated in MDA-MB-231 cells in response to IGF-I and that this is dependent on PI3Kγ activity.Conclusions
Our data imply a novel role for PI3Kγ in facilitating cell migration by regulating phosphorylation of eEF2. 相似文献12.
13.
Yue Sun Chengli Du Bo Wang Yanling Zhang Xiaoyan Liu Guoping Ren 《Biochemical and biophysical research communications》2014
Background
eEF1A2 is a protein translation factor involved in protein synthesis, which possesses important function roles in cancer development. This study aims at investigating the expression pattern of eEF1A2 in prostate cancer and its potential role in prostate cancer development.Methods
We examined the expression level of eEF1A2 in 30 pairs of prostate cancer tissues by using RT-PCR and immunohistochemical staining (IHC). Then we applied siRNA specifically targeting eEF1A2 to down-regulate its expression in DU-145 and PC-3 cells. Flow cytometer was used to explore apoptosis and Western-blot was used to detect the pathway proteins of apoptosis.Results
Our results showed that the expression level of eEF1A2 in prostate cancer tissues was significantly higher compared to their corresponding normal tissues. Reduction of eEF1A2 expression in DU-145 and PC-3 cells led to a dramatic inhibition of proliferation accompanied with enhanced apoptosis rate. Western blot revealed that apoptosis pathway proteins (caspase3, BAD, BAX, PUMA) were significantly up-regulated after suppression of eEF1A2. More importantly, the levels of eEF1A2 and caspase3 were inversely correlated in prostate cancer tissues.Conclusion
Our data suggests that eEF1A2 plays an important role in prostate cancer development, especially in inhibiting apoptosis. So eEF1A2 might serve as a potential therapeutic target in prostate cancer. 相似文献14.
Yvette R. Pittman Kimberly Kandl Marcus Lewis Louis Valente Terri Goss Kinzy 《The Journal of biological chemistry》2009,284(7):4739-4747
Eukaryotic translation elongation factor 1A (eEF1A) both shuttles
aminoacyl-tRNA (aa-tRNA) to the ribosome and binds and bundles actin. A single
domain of eEF1A is proposed to bind actin, aa-tRNA and the guanine nucleotide
exchange factor eEF1Bα. We show that eEF1Bα has the ability to
disrupt eEF1A-induced actin organization. Mutational analysis of eEF1Bα
F163, which binds in this domain, demonstrates effects on growth, eEF1A
binding, nucleotide exchange activity, and cell morphology. These phenotypes
can be partially restored by an intragenic W130A mutation. Furthermore, the
combination of F163A with the lethal K205A mutation restores viability by
drastically reducing eEF1Bα affinity for eEF1A. This also results in a
consistent increase in actin bundling and partially corrected morphology. The
consequences of the overlapping functions in this eEF1A domain and its unique
differences from the bacterial homologs provide a novel function for
eEF1Bα to balance the dual roles in actin bundling and protein
synthesis.The final step of gene expression takes place at the ribosome as mRNA is
translated into protein. In the yeast Saccharomyces cerevisiae,
elongation of the polypeptide chain requires the orchestrated action of three
soluble factors. The eukaryotic elongation factor 1
(eEF1)2 complex
delivers aminoacyl-tRNA (aa-tRNA) to the empty A-site of the elongating
ribosome (1). The eEF1A subunit
is a classic G-protein that acts as a “molecular switch” for the
active and inactive states based on whether GTP or GDP is bound, respectively
(2). Once an anticodon-codon
match occurs, the ribosome acts as a GTPase-activating factor to stimulate GTP
hydrolysis resulting in the release of inactive GDP-bound eEF1A from the
ribosome. Because the intrinsic rate of GDP release from eEF1A is extremely
slow (3,
4), a guanine nucleotide
exchange factor (GEF) complex, eEF1B, is required
(5,
6). The yeast S.
cerevisiae eEF1B complex contains two subunits, the essential catalytic
subunit eEF1Bα (5) and
the non-essential subunit eEF1Bγ
(7).The co-crystal structures of eEF1A:eEF1Bα C terminus:GDP:
Mg2+ and eEF1A:eEF1Bα C terminus:GDPNP
(8,
9) demonstrated a surprising
structural divergence from the bacterial EF-Tu-EF-Ts
(10) and mammalian
mitochondrial EF-Tumt-EF-Tsmt
(11). While the G-proteins
have a similar topology and consist of three well-defined domains, a striking
difference was observed in binding sites for their GEFs. The C terminus of
eEF1Bα interacts with domain I and a distinct pocket of domain II eEF1A,
creating two binding interfaces. In contrast, the bacterial counterpart EF-Ts
and mammalian mitochondrial EF-Tsmt, make extensive contacts with
domain I and III of EF-Tu and EF-Tumt, respectively. The altered
binding interface of eEF1Bα to domain II of eEF1A is particularly
unexpected given the functions associated with domain II of eEF1A and EF-Tu.
The crystal structure of the EF-Tu:GDPNP:Phe-tRNAPhe complex
reveals aa-tRNA binding to EF-Tu requires only minor parts of both domain II
and tRNA to sustain stable contacts
(12). That eEF1A employs the
same aa-tRNA binding site is supported by genetic and biochemical data
(13-15).
Interestingly, eEF1Bα contacts many domain II eEF1A residues in the
region hypothesized to be involved in the binding of the aa-tRNA CCA end
(8). Because, the shared
binding site of eEF1Bα and aa-tRNA on domain II of eEF1A is
significantly different between the eukaryotic and bacterial/mitochondrial
systems, eEF1Bα may play a unique function aside from guanine nucleotide
release in eukaryotes.In eukaroytes, eEF1A is also an actin-binding and -bundling protein. This
noncanonical function of eEF1A was initially observed in Dictyostelium
amoebae (16). It is
estimated that greater than 60% of Dictyostelium eEF1A is associated
with the actin cytoskeleton
(17). The eEF1A-actin
interaction is conserved among species from yeast to mammals, suggesting the
importance of eEF1A for cytoskeleton integrity. Using a unique genetic
approach, multiple eEF1A mutations were identified that altered cell growth
and morphology, and are deficient in bundling actin in vitro
(18,
19). Intriguingly, most
mutations localized to domain II, the shared aa-tRNA and eEF1Bα binding
site. Previous studies have demonstrated that actin bundling by eEF1A is
significantly reduced in the presence of aa-tRNA while eEF1A bound to actin
filaments is not in complex with aa-tRNA
(20). Therefore, actin and
aa-tRNA binding to eEF1A is mutually exclusive. In addition, overexpression of
yeast eEF1A or actin-bundling deficient mutants do not affect translation
elongation (18,
19,
21), suggesting
eEF1A-dependent cytoskeletal organization is independent of its translation
elongation function (18,
20). Thus, while aa-tRNA
binding to domain II is conserved between EF-Tu and eEF1A, this actin bundling
function associated with eEF1A domain II places greater importance on its
relationship with the “novel” binding interface between eEF1A
domain II and eEF1Bα.Based on this support for an overlapping actin bundling and eEF1Bα
binding site in eEF1A domain II, we hypothesize that eEF1Bα modulates
the equilibrium between actin and translation functions of eEF1A and is
perhaps the result of evolutionary selective pressure to balance the
eukaryotic-specific role of eEF1A in actin organization. Here, we present
kinetic and biochemical evidence using a F163A mutant of eEF1Bα for the
importance of the interactions between domain II of eEF1A and eEF1Bα to
prevent eEF1A-dependent actin bundling as well as promoting guanine nucleotide
exchange. Furthermore, altered affinities of eEF1Bα mutants for eEF1A
support that this complex formation is a determining factor for eEF1A-induced
actin organization. Interestingly, the F163A that reduces eEF1A affinity is an
intragenic suppressor of the lethal K205A eEF1Bα mutant that displays
increased affinity for eEF1A. This, along with a consistent change in the
actin bundling correlated with the affinity of eEF1Bα for eEF1A,
indicates that eEF1Bα is a balancer, directing eEF1A to translation
elongation and away from actin, and alterations in this balance result in
detrimental effects on cell growth and eEF1A function. 相似文献
15.
Joshua J. Hamey Daniel L. Winter Daniel Yagoub Christopher M. Overall Gene Hart-Smith Marc R. Wilkins 《Molecular & cellular proteomics : MCP》2016,15(1):164-176
Eukaryotic elongation factor 1A (eEF1A) is an essential, highly methylated protein that facilitates translational elongation by delivering aminoacyl-tRNAs to ribosomes. Here, we report a new eukaryotic protein N-terminal methyltransferase, Saccharomyces cerevisiae YLR285W, which methylates eEF1A at a previously undescribed high-stoichiometry N-terminal site and the adjacent lysine. Deletion of YLR285W resulted in the loss of N-terminal and lysine methylation in vivo, whereas overexpression of YLR285W resulted in an increase of methylation at these sites. This was confirmed by in vitro methylation of eEF1A by recombinant YLR285W. Accordingly, we name YLR285W as elongation factor methyltransferase 7 (Efm7). This enzyme is a new type of eukaryotic N-terminal methyltransferase as, unlike the three other known eukaryotic N-terminal methyltransferases, its substrate does not have an N-terminal [A/P/S]-P-K motif. We show that the N-terminal methylation of eEF1A is also present in human; this conservation over a large evolutionary distance suggests it to be of functional importance. This study also reports that the trimethylation of Lys79 in eEF1A is conserved from yeast to human. The methyltransferase responsible for Lys79 methylation of human eEF1A is shown to be N6AMT2, previously documented as a putative N(6)-adenine-specific DNA methyltransferase. It is the direct ortholog of the recently described yeast Efm5, and we show that Efm5 and N6AMT2 can methylate eEF1A from either species in vitro. We therefore rename N6AMT2 as eEF1A-KMT1. Including the present work, yeast eEF1A is now documented to be methylated by five different methyltransferases, making it one of the few eukaryotic proteins to be extensively methylated by independent enzymes. This implies more extensive regulation of eEF1A by this posttranslational modification than previously appreciated.Protein methylation is emerging as one of the most prominent posttranslational modifications in the eukaryotic cell (1). Often showing high evolutionary conservation, it is increasingly recognized for its role in modulating protein–protein interactions (2). Indeed, it has been documented in protein interaction codes (3), such as those of the histones and p53 (4, 5), where it shows interplay with modifications such as acetylation and phosphorylation. Despite this, there remains a paucity of understanding of the enzymes that catalyze protein methylation. Many of the known methyltransferases target histones. However, many other methyltransferases have been discovered recently that act on nonhistone proteins (6).While protein methylation predominantly occurs on lysine and arginine residues, it is also known to occur on glutamine, asparagine, glutamate, histidine, cysteine, and the N- and C termini of proteins. Although the presence of N-terminal methylation on numerous proteins has been known for decades (7), the first enzymes responsible for this methylation have only recently been discovered (8, 9). The Saccharomyces cerevisiae protein Tae1 and its human ortholog N-terminal methyltransferase 1 (NTMT1) catalyze N-terminal methylation of proteins with an N-terminal [A/P/S]-P-K motif (after methionine removal). Yet there is evidence that these enzymes may recognize a more general N-terminal motif (10). Human NTMT2 is a monomethyltransferase that methylates the same substrates as NTMT1 and may prime substrate proteins with monomethylation to assist subsequent trimethylation by NTMT1 (11).The biological function of N-terminal methylation on some proteins has been recently revealed. For example, N-terminal methylation of regulator of chromatin condensation protein 1 (RCC1) is known to affect its binding to chromatin and thereby the correct chromosomal segregation during mitosis (12, 13), and N-terminal methylation of DNA damage-binding protein 2 (DDB2) is important for its role in UV-damaged DNA repair (14). Interestingly, there is evidence of interplay between N-terminal methylation and other posttranslational modifications (15), suggesting that, like lysine and arginine methylation, it may be incorporated into protein interaction codes (3). N-terminal methylation therefore appears to be a modification of functional importance in the cell.Eukaryotic elongation factor 1A (eEF1A), and its bacterial ortholog EF-Tu, is an essential translation elongation factor that is found in all living organisms. Its canonical function is in facilitating delivery of aminoacyl-tRNAs to the ribosome; however, it is also known to have a role in many other cellular functions, such as actin bundling, nuclear export, and proteasomal degradation (16). A number of methyltransferases have been discovered in both S. cerevisiae and human that target translation elongation factors. In yeast, four of these elongation factor methyltransferases (EFMs) act on eEF1A, namely Efm1, Efm4, Efm5, and Efm6, generating monomethylated Lys30, dimethylated Lys316, trimethylated Lys79, and monomethylated Lys390, respectively (17–19). Human METTL10 is the ortholog of Efm4 in that it trimethylates eEF1A at Lys318, which is equivalent to Lys316 in yeast (20). Interestingly, eukaryotic elongation factor 2 (eEF2) is also methylated by a number of lysine methyltransferases. In yeast, Efm2 and Efm3 act on eEF2, generating dimethylated Lys613 and trimethylated Lys509, respectively (21–24). Human eEF2-KMT is the ortholog of Efm3 in that it trimethylates eEF2 at Lys525, which is equivalent to Lys509 in yeast eEF2 (23).Here, we report the N-terminal methylation of eEF1A in S. cerevisiae and the identification of the methyltransferase that catalyzes this event. Using parallel reaction monitoring and MS/MS/MS (MS3), we unambiguously localize the modification to the N-terminal glycine and show it is conserved in the human cell. We also show that YLR285W, which we rename elongation factor methyltransferase 7 (Efm7), is responsible for this modification in yeast, as well as dimethylation at the adjacent lysine. We also characterize the methyltransferases responsible for methylation of lysine 79 in eEF1A. Human N6AMT2 is shown to be the ortholog of yeast Efm5 through its capacity to methylate yeast and human eEF1A at Lys79
in vitro. We therefore rename N6AMT2 as eEF1A-KMT1. 相似文献
16.
Background
The genetic basis of telomere length heterogeneity among mammalian species is still not well understood. Recently, a gene named regulator of telomere length elongation helicase (RTEL) was identified and predicted to be an essential participant in species-specific telomere length regulation in two murine species. To obtain broader insights into its structure and biological functions and to ascertain whether RTEL is also a candidate gene in the regulation of telomere length diversity in other mammalian species, data from other mammals may be helpful. 相似文献17.
Translation elongation is mediated by ribosomes and multiple soluble factors, many of which are conserved across bacteria and eukaryotes. During elongation, eukaryotic elongation factor 1A (eEF1A; EF-Tu in bacteria) delivers aminoacylated-tRNA to the A-site of the ribosome, whereas eEF2 (EF-G in bacteria) translocates the ribosome along the mRNA. Fungal translation elongation is striking in its absolute requirement for a third factor, the ATPase eEF3. eEF3 binds close to the E-site of the ribosome and has been proposed to facilitate the removal of deacylated tRNA from the E-site. eEF3 has two ATP binding cassette (ABC) domains, the second of which carries a unique chromodomain-like insertion hypothesized to play a significant role in its binding to the ribosome. This model was tested in the current study using a mutational analysis of the Sac7d region of the chromodomain-like insertion. Specific mutations in this domain result in reduced growth rate as well as slower translation elongation. In vitro analysis demonstrates that these mutations do not affect the ability of eEF3 to interact with the ribosome. Kinetic analysis revealed a larger turnover number for ribosomes in comparison to eEF3, indicating that the partial reactions involving the ribosome are significantly faster than that of eEF3. Mutations in the chromodomain-like insertion severely compromise the ribosome stimulated ATPase of eEF3, strongly suggesting that it exerts an allosteric effect on the hydrolytic activity of eEF3. The chromodomain-like insertion is, therefore, vital to eEF3 function and may be targeted for developing novel antifungal drugs. 相似文献
18.
Muhammad Irshad Hervé Canut Gisèle Borderies Rafael Pont-Lezica Elisabeth Jamet 《BMC plant biology》2008,8(1):94
Background
Cell elongation in plants requires addition and re-arrangements of cell wall components. Even if some protein families have been shown to play roles in these events, a global picture of proteins present in cell walls of elongating cells is still missing. A proteomic study was performed on etiolated hypocotyls of Arabidopsis used as model of cells undergoing elongation followed by growth arrest within a short time. 相似文献19.
Namit Ranjan Agnieszka A Pochopien Colin ChihChien Wu Bertrand Beckert Sandra Blanchet Rachel Green Marina V Rodnina Daniel N Wilson 《The EMBO journal》2021,40(6)
In addition to the conserved translation elongation factors eEF1A and eEF2, fungi require a third essential elongation factor, eEF3. While eEF3 has been implicated in tRNA binding and release at the ribosomal A and E sites, its exact mechanism of action is unclear. Here, we show that eEF3 acts at the mRNA–tRNA translocation step by promoting the dissociation of the tRNA from the E site, but independent of aminoacyl‐tRNA recruitment to the A site. Depletion of eEF3 in vivo leads to a general slowdown in translation elongation due to accumulation of ribosomes with an occupied A site. Cryo‐EM analysis of native eEF3‐ribosome complexes shows that eEF3 facilitates late steps of translocation by favoring non‐rotated ribosomal states, as well as by opening the L1 stalk to release the E‐site tRNA. Additionally, our analysis provides structural insights into novel translation elongation states, enabling presentation of a revised yeast translation elongation cycle. 相似文献
20.