Control of the amount and functionality of the eEF1A1 and eEF1A2 isoforms in mammalian cells

Aim. To review mechanisms of regulation of expression and the functionality of two isoforms of translation elongation factor eEF1A in mammalian cells. Results. eEF1A1 and eEF1A2 proteins are regulated by post-translational modifications, protein-protein and protein-tRNA interactions as well as by controlling the amount of their mRNAs in human cells. Conclusions. EEF1A1 mRNA levels in cancer cells may depend on the allelic copy number while the level of EEF1A2 mRNA may be controlled by micro RNAs. eEF1A2 protein activity in different cellular processes may be determined, in part, by its increased affinity for tRNA and viral RNAs as compared to eEF1A1. eEF1A1 activity can be regulated by its increased susceptibility to post-translational modifications (PTM) and protein-protein interactions (PTI) as compared to eEF1A2.Мета. Представити короткий огляд деяких механізмів, за допомогою яких клітини ссавців контролюють експресію і функціональність двох ізоформ фактора елонгації трансляції eEF1A. Результати. Описано клітинну тактику контроля білків eEF1A1 і eEF1A2 за участі пост-трансляційних модифікацій, білок-білкових та білок-РНКових взаємодій, а також регуляції кількості і стабільності EEF1A1 і EEF1A2 мРНК. Висновки. Рівень мРНК, що кодує еEF1A1 в ракових клітинах, може залежати від зміни кількості алельних копій, у той час, коли рівень EEF1A2 мРНК може контролюватися за допомогою мікро РНК. Активність білка еEF1A2 в різних клітинних процесах, може визначатися, зокрема, підвищеною, в порівнянні з еEF1A1, афінністю до тРНК і вірусної РНК. В свою чергу, активність еEF1A1 може регулюватися підвищеною, в порівнянні з еF1A2, доступністю цього білка до пост-трансляційних модифікацій і білок-білкових взаємодій.Цель. Представить краткий обзор некоторых механизмов, с помощью которых клетки млекопитающих контролируют экспрессию и функциональность двух изоформ фактора элонгации трансляции еEF1A. Результаты. Описано клеточную тактику контроля белков eEF1A1 и eEF1A2 с участием пост-трансляционных модификаций, белок-белковых и белок-РНКовых взаимодействий, а также регуляции количества и стабильности EEF1A1 и EEF1A2 мРНК. Выводы. Уровень мРНК, которая кодирует еEF1A1 в раковых клетках, может определяться измененным количеством аллельных копий, в то время как уровень мРНК, кодирующей еEF1A2, может контролироваться посредством микроРНК. Активность белка еEF1A2 в разных клеточных процессах может определяться, в частности, его увеличенной, в сравнении с eEF1A1, аффинностью к тРНК и вирусной РНК. В свою очередь, активность eEF1A1 может регулироваться увеличенными, по сравнению с eEF1A2, подверженностью этого белка пост-трансляционным модификациям и доступностью для белок-белковых взаимодействий

Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes

We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress

Two-dimensional gel electrophoresis in proteomics: past, present and future

Two-dimensional gel electrophoresis has been instrumental in the birth and developments of proteomics, although it is no longer the exclusive separation tool used in the field of proteomics. In this review, a historical perspective is made, starting from the days where two-dimensional gels were used and the word proteomics did not even exist. The events that have led to the birth of proteomics are also recalled, ending with a description of the now well-known limitations of two-dimensional gels in proteomics. However, the often-underestimated advantages of two-dimensional gels are also underlined, leading to a description of how and when to use two-dimensional gels for the best in a proteomics approach. Taking support of these advantages (robustness, resolution, and ability to separate entire, intact proteins), possible future applications of this technique in proteomics are also mentioned

Proteomics: A powerful tool in the post-genomic era

360-368Genomics is having a profound impact on biological research, including photosynthesis investigations. Genomes of many photosynthetic organisms have been sequenced. The information about ALL genes that govern and execute photoautotrophic metabolism provides many opportunities to understand genome function and details of known and uncharted pathways. Proteomics, analysis of the protein complement of the genome, is a powerful tool in understanding which proteins are present in a particular tissue under given conditions. Proteomics also allows us to estimate relative levels of proteins and to determine post-translational modifications of the gene products. In this minireview, we discuss the technology and its applications in plant sciences.</span

The eEF1 family of mammalian translation elongation factors

The eEF1 family of mammalian translation elongation factors is comprised of the two variants of eEF1A (eEF1A1 and eEF1A2), and the eEF1B complex. The latter consists of eEF1Bα, eEF1Bβ, and eEF1Bγ subunits. The two eEF1A variants have similar translation activity but may differ with respect to their secondary, “moonlighting” functions. This variability is underlined by the difference in the spatial organization of eEF1A1 and eEF1A2, and also possibly by the differences in their post-translational modifications. Here, we review the data on the spatial organization and post-translation modifications of eEF1A1 and eEF1A2, and provide examples of their involvement in various processes in addition to translation. We also describe the structural models of eEF1B subunits, their organization in the subcomplexes, and the trimeric model of the entire eEF1B complex. We discuss the functional consequences of such an assembly into a complex as well as the involvement of individual subunits in non-translational processes