Analysis of eEF1Bγ interactome in the nuclear fraction of A549 human lung adenocarcinoma cells

Abstract

Aim.To study the translation elongation factor eEF1B gamma (eEF1Bγ) in the nucleus of lung carcinoma cells. Methods. The protein partners of eEF1Bγin the nuclear fraction of A549 cells were identified by co-immunoprecipitation (co-IP) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The protein interaction network for nuclear eEF1Bγ was determined by Cytoscape 3.2.0 program using the MCODE plugin. Additional analysis of the eEF1Bγ partners was conducted by Map of the cell database. Results. 234 proteins interacting with eEF1Bγ in the nuclear fraction of A549 cells were identified. Possible functional networks involving these contacts were analyzed by two bioinformatic approaches. Conclusions. Splicing of pre-mRNA and regulation of mRNA stability are assumed to be the main processes in which nuclear eEF1Bγ can be involved. We hypothesize that a portion of eEF1Bγ leaves the cytoplasmlocalizede EF1B complex during carcinogenesis and enters the nucleus to regulate certain mRNAs by affecting the splicing of their pre-mRNA and/or stability of mRNA. K e y w o r d s: eEF1Bγ, protein-protein interactions, nucleus, A549 cell Structure and Function of Biopolymers

Non-translational Connections of eEF1B in the Cytoplasm and Nucleus of Cancer Cells

“…However, signs of the nuclear localization of eEF1B subunits were displayed in the normal (Drosophila embryos, human cardioesophageal junction, human lung) and cancer (cardioesophageal carcinoma, lung cancer, oral squamous cell carcinoma) tissues as well as in lung adenocarcinoma cells A549 (Fan et al, 2010;Veremieva et al, 2011;Veremieva et al, 2014;Flores et al, 2016). In an attempt to attribute possible noncanonical eEF1B functions to the specific cellular compartments the partners of eEF1Bβ and eEF1Bγ in the cytoplasm and nucleus of human lung carcinoma cells were identified experimentally and analyzed by several bioinformatics approaches (Kapustian et al, 2016(Kapustian et al, , 2017(Kapustian et al, , 2018(Kapustian et al, , 2019. Cytoplasmic eEF1Bβ was predicted to be involved into four protein networks representing cell cycle regulation, DNA replication and repair, chromatin remodeling and chaperoning machinery (Kapustian et al, 2016).…”

“…Cytoplasmic eEF1Bγ could participate in mRNA splicing and processing, nucleosome remodeling, cell cycle regulation, viral RNA transcription, oxidative stress response (Kapustian et al, 2018). Nuclear eEF1Bγ supposedly took part in splicing of pre-mRNA and regulation of mRNA stability, cytoskeleton-membrane linking and cellular trafficking (Kapustian et al, 2019).…”

“…Taking into account the above-mentioned trends toward the coordinated upregulation of eEF1Bβ and eEF1Bγ in human cancer tissues it would be interesting to decipher the processes in which these subunits may be involved in concert. For the cytoplasmic fraction, those are, surprisingly, chromatin/nucleosome remodeling and cell cycle regulation (Kapustian et al, 2016(Kapustian et al, , 2018 while for the nuclear fraction it is regulation of the mRNA stability and degradation (Kapustian et al, 2017(Kapustian et al, , 2019. One should mention, however, that mixed intracellular localization is characteristic for components of these processes in cell.…”

“…One should mention, however, that mixed intracellular localization is characteristic for components of these processes in cell. Besides, a number of processes may involve both cyto-and nucleo-localized eEF1Bβ and eEF1Bγ; these are microRNA turnover, cytoskeleton-membrane linking, cellular trafficking, mRNA transcription and splicing (Kapustian et al, 2016(Kapustian et al, , 2017(Kapustian et al, , 2018(Kapustian et al, , 2019. This apparently reflects cytonucleo shuttling of subunits involved into these processes.…”

“…The viral infection-related functions of the eEF1B complex well described in Li et al (2013) are not a subject of this minireview, though some virus-related partners of eEF1B subunits were found in the cytoplasmic and nuclear fractions of lung carcinoma cells (Kapustian et al, 2017;Kapustian et al, 2018;Kapustian et al, 2019).…”