Cytosolic Ribosomes Research Articles

Studying Protein Import into Chloroplasts Using Protoplasts.

The chloroplast is an essential organelle that is responsible for various cellular processes in plants, such as photosynthesis and the production of many secondary metabolites and lipids. Chloroplasts require a large number of proteins for these various physiological processes. Over 95% of chloroplast proteins are nucleus-encoded and imported into chloroplasts from the cytosol after translation on cytosolic ribosomes. Thus, the proper import or targeting of these nucleus-encoded chloroplast proteins to chloroplasts is essential for the proper functioning of chloroplasts as well as the plant cell. Nucleus-encoded chloroplast proteins contain signal sequences for specific targeting to chloroplasts. Molecular machinery localized to the chloroplast or cytosol recognize these signals and carry out the import process. To investigate the mechanisms of protein import or targeting to chloroplasts in vivo, we developed a rapid, efficient protoplast-based method to analyze protein import into chloroplasts of Arabidopsis. In this method, we use protoplasts isolated from leaf tissues of Arabidopsis. Here, we provide a detailed protocol for using protoplasts to investigate the mechanism by which proteins are imported into chloroplasts.

Regulation of mitochondrion-associated cytosolic ribosomes by mammalian mitochondrial ribonuclease T2 (RNASET2)

Mitochondrial proteins are encoded in both mitochondrial and nuclear genomes. The expression levels of these two pools of mitochondrial genes are co-regulated and synchronized. Import and assembly of the nucleus-encoded oxidative phosphorylation (OXPHOS) subunits affect protein synthesis in the mitochondrial matrix by engaging the mitochondrial ribosomes. How the ribosomes at the outside of mitochondria are regulated by mitochondria, however, remains mostly unexplored. Here, using an array of biochemical assays and genetic knockdown and overexpression in HEK293 or mouse cells, we show that cytosolic rRNAs that are associated with the mitochondrial outer membrane have very different decay patterns from those of both endoplasmic reticulum–associated and –nonassociated cytosolic rRNAs. Mitochondrial intermembrane space RNase T2 (RNASET2), which has been previously shown to degrade mitochondrial RNAs, is also responsible for selective degradation of the cytosolic rRNAs on the outer membrane. We noted that the degradation activity also has a positive effect on nuclear transcription of rRNAs, suggesting a compensatory feedback mechanism, and affects protein translations in and out of mitochondria. These findings establish a mechanism for the co-regulation of gene expression programs inside and outside of mitochondria in mammalian cells.

Formyl-methionine as an N-degron of a eukaryotic N-end rule pathway.

In bacteria, nascent proteins bear the pretranslationally generated N-terminal (Nt) formyl-methionine (fMet) residue. Nt-fMet of bacterial proteins is a degradation signal, termed fMet/N-degron. By contrast, proteins synthesized by cytosolic ribosomes of eukaryotes were presumed to bear unformylated Nt-Met. Here we found that the yeast formyltransferase Fmt1, although imported into mitochondria, could also produce Nt-formylated proteins in the cytosol. Nt-formylated proteins were strongly up-regulated in stationary phase or upon starvation for specific amino acids. This up-regulation strictly required the Gcn2 kinase, which phosphorylates Fmt1 and mediates its retention in the cytosol. We also found that the Nt-fMet residues of Nt-formylated proteins act as fMet/N-degrons and identified the Psh1 ubiquitin ligase as the recognition component of the eukaryotic fMet/N-end rule pathway, which destroys Nt-formylated proteins.

Rapid Isolation of the Mitoribosome from HEK Cells.

The human mitochondria possess a dedicated set of ribosomes (mitoribosomes) that translate 13 essential protein components of the oxidative phosphorylation complexes encoded by the mitochondrial genome. Since all proteins synthesized by human mitoribosomes are integral membrane proteins, human mitoribosomes are tethered to the mitochondrial inner membrane during translation. Compared to the cytosolic ribosome the mitoribosome has a sedimentation coefficient of 55S, half the rRNA content, no 5S rRNA and 36 additional proteins. Therefore, a higher protein-to-RNA ratio and an atypical structure make the human mitoribosome substantially distinct from its cytosolic counterpart. Despite the central importance of the mitoribosome to life, no protocols were available to purify the intact complex from human cell lines. Traditionally, mitoribosomes were isolated from mitochondria-rich animal tissues that required kilograms of starting material. We reasoned that mitochondria in dividing HEK293-derived human cells grown in nutrient-rich expression medium would have an active mitochondrial translation, and, therefore, could be a suitable source of material for the structural and biochemical studies of the mitoribosome. To investigate its structure, we developed a protocol for large-scale purification of intact mitoribosomes from HEK cells. Herein, we introduce nitrogen cavitation method as a faster, less labor-intensive and more efficient alternative to traditional mechanical shear-based methods for cell lysis. This resulted in preparations of the mitoribosome that allowed for its structural determination to high resolution, revealing the composition of the intact human mitoribosome and its assembly intermediates. Here, we follow up on this work and present an optimized and more cost-effective method requiring only ~1010 cultured HEK cells. The method can be employed to purify human mitoribosomal translating complexes, mutants, quality control assemblies and mitoribosomal subunits intermediates. The purification can be linearly scaled up tenfold if needed, and also applied to other types of cells.

Rapid Isolation of the Mitoribosome from HEK Cells

The human mitochondria possess a dedicated set of ribosomes (mitoribosomes) that translate 13 essential protein components of the oxidative phosphorylation complexes encoded by the mitochondrial genome. Since all proteins synthesized by human mitoribosomes are integral membrane proteins, human mitoribosomes are tethered to the mitochondrial inner membrane during translation. Compared to the cytosolic ribosome the mitoribosome has a sedimentation coefficient of 55S, half the rRNA content, no 5S rRNA and 36 additional proteins. Therefore, a higher protein-to-RNA ratio and an atypical structure make the human mitoribosome substantially distinct from its cytosolic counterpart. Despite the central importance of the mitoribosome to life, no protocols were available to purify the intact complex from human cell lines. Traditionally, mitoribosomes were isolated from mitochondria-rich animal tissues that required kilograms of starting material. We reasoned that mitochondria in dividing HEK293-derived human cells grown in nutrient-rich expression medium would have an active mitochondrial translation, and, therefore, could be a suitable source of material for the structural and biochemical studies of the mitoribosome. To investigate its structure, we developed a protocol for large-scale purification of intact mitoribosomes from HEK cells. Herein, we introduce nitrogen cavitation method as a faster, less labor-intensive and more efficient alternative to traditional mechanical shear-based methods for cell lysis. This resulted in preparations of the mitoribosome that allowed for its structural determination to high resolution, revealing the composition of the intact human mitoribosome and its assembly intermediates. Here, we follow up on this work and present an optimized and more cost-effective method requiring only ~1010 cultured HEK cells. The method can be employed to purify human mitoribosomal translating complexes, mutants, quality control assemblies and mitoribosomal subunits intermediates. The purification can be linearly scaled up tenfold if needed, and also applied to other types of cells.

Pathways to balance mitochondrial translation and protein import.

Mitochondria contain their own genome that encodes for a small number of proteins, while the vast majority of mitochondrial proteins is produced on cytosolic ribosomes. The formation of respiratory chain complexes depends on the coordinated biogenesis of mitochondrially encoded and nuclear-encoded subunits. In this review, we describe pathways that adjust mitochondrial protein synthesis and import of nuclear-encoded subunits to the assembly of respiratory chain complexes. Furthermore, we outline how defects in protein import into mitochondria affect nuclear gene expression to maintain protein homeostasis under physiological and stress conditions.

Dual or Not Dual?-Comparative Analysis of Fluorescence Microscopy-Based Approaches to Study Organelle Targeting Specificity of Nuclear-Encoded Plant Proteins.

Plant cells are unique as they carry two organelles of endosymbiotic origin, namely mitochondria and chloroplasts (plastids) which have specific but partially overlapping functions, e. g., in energy and redox metabolism. Despite housing residual genomes of limited coding capacity, most of their proteins are encoded in the nucleus, synthesized by cytosolic ribosomes and need to be transported “back” into the respective target organelle. While transport is in most instances strictly monospecific, a group of proteins carries “ambiguous” transit peptides mediating transport into both, mitochondria and plastids. However, such dual targeting is often disputed due to variability in the results obtained from different experimental approaches. We have therefore compared and evaluated the most common methods established to study protein targeting into organelles within intact plant cells. All methods are based on fluorescent protein technology and live cell imaging. For our studies, we have selected four candidate proteins with proven dual targeting properties and analyzed their subcellular localization in vivo utilizing four different methods (particle bombardment, protoplast transformation, Agrobacterium infiltration, and transgenic plants). Though using identical expression constructs in all instances, a given candidate protein does not always show the same targeting specificity in all approaches, demonstrating that the choice of method is important, and depends very much on the question to be addressed.

Dynamic Proteomic and miRNA Analysis of Polysomes from Isolated Mouse Heart After Langendorff Perfusion.

Studies in dynamic changes in protein translation require specialized methods. Here we examined changes in newly-synthesized proteins in response to ischemia and reperfusion using the isolated perfused mouse heart coupled with polysome profiling. To further understand the dynamic changes in protein translation, we characterized the mRNAs that were loaded with cytosolic ribosomes (polyribosomes or polysomes) and also recovered mitochondrial polysomes and compared mRNA and protein distribution in the high-efficiency fractions (numerous ribosomes attached to mRNA), low-efficiency (fewer ribosomes attached) which also included mitochondrial polysomes, and the non-translating fractions. miRNAs can also associate with mRNAs that are being translated, thereby reducing the efficiency of translation, we examined the distribution of miRNAs across the fractions. The distribution of mRNAs, miRNAs, and proteins was examined under basal perfused conditions, at the end of 30 min of global no-flow ischemia, and after 30 min of reperfusion. Here we present the methods used to accomplish this analysis-in particular, the approach to optimization of protein extraction from the sucrose gradient, as this has not been described before-and provide some representative results.

Analysis of Mitochondrial Protein Synthesis: De Novo Translation, Steady-State Levels, and Assembled OXPHOS Complexes.

Mitochondria are multifunctional organelles with their own genome and protein synthesis machinery. The 13 proteins encoded by mitochondrial DNA (mtDNA) are core subunits of the oxidative phosphorylation (OXPHOS) system producing the majority of cellular ATP. Yet most mitochondrial proteins are encoded by nuclear genes, synthesized by cytosolic ribosomes, and imported into mitochondria. Therefore, disturbances in cytosolic proteostasis have consequences on the gene expression and synthesis of mtDNA-encoded proteins and overall on mitochondrial function. Internal and environmental factors such as mutations, aging, oxidative stress, and toxic agents can affect the translation and the stability of mitochondrial proteins and lead to OXPHOS dysfunction. Here, methods for analysis of mitochondrial translation rate and protein stability using radioactive and non-radioactive technique as well as the methods for studying steady-state levels and assembly of OXPHOS complexes are described. © 2018 by John Wiley & Sons, Inc.

Novel insights into global translational regulation through Pumilio family RNA-binding protein Puf3p revealed by ribosomal profiling

RNA binding proteins (RBPs) can regulate the stability, localization, and translation of their target mRNAs. Among them, Puf3p is a well-known Pumilio family RBP whose biology has been intensively studied. Nevertheless, the impact of Puf3p on the translational regulation of its downstream genes still remains to be investigated at the genome-wide level. In this study, we combined ribosome profiling and RNA-Seq in budding yeast (Saccharomyces cerevisiae) to investigate Puf3p's functions in translational regulation. Comparison of translational efficiency (TE) between wild-type and puf3Δ strains demonstrates extensive translational modulation in the absence of Puf3p (over 27% genes are affected at the genome level). Besides confirming its known role in regulating mitochondrial metabolism, our data demonstrate that Puf3p serves as a key post-transcriptional regulator of downstream RBPs by regulating their translational efficiencies, indicating a network of interactions among RBPs at the post-transcriptional level. Furthermore, Puf3p switches the balance of translational flux between mitochondrial and cytosolic ribosome biogenesis to adapt to changes in cellular metabolism. In summary, our results indicate that TE can be utilized as an informative index to interrogate the mechanism underlying RBP functions, and provide novel insights into Puf3p's mode-of-action.

Cytosolic Hsp70 and Hsp40 chaperones enable the biogenesis of mitochondrial β-barrel proteins.

Mitochondrial β-barrel proteins are encoded in the nucleus, translated by cytosolic ribosomes, and then imported into the organelle. Recently, a detailed understanding of the intramitochondrial import pathway of β-barrel proteins was obtained. In contrast, it is still completely unclear how newly synthesized β-barrel proteins reach the mitochondrial surface in an import-competent conformation. In this study, we show that cytosolic Hsp70 chaperones and their Hsp40 cochaperones Ydj1 and Sis1 interact with newly synthesized β-barrel proteins. These interactions are highly relevant for proper biogenesis, as inhibiting the activity of the cytosolic Hsp70, preventing its docking to the mitochondrial receptor Tom70, or depleting both Ydj1 and Sis1 resulted in a significant reduction in the import of such substrates into mitochondria. Further experiments demonstrate that the interactions between β-barrel proteins and Hsp70 chaperones and their importance are conserved also in mammalian cells. Collectively, this study outlines a novel mechanism in the early events of the biogenesis of mitochondrial outer membrane β-barrel proteins.

Plant Temperature Acclimation and Growth Rely on Cytosolic Ribosome Biogenesis Factor Homologs.

Arabidopsis (Arabidopsis thaliana) REI1-LIKE (REIL) proteins, REIL1 and REIL2, are homologs of a yeast ribosome biogenesis factor that participates in late cytoplasmic 60S ribosomal subunit maturation. Here, we report that the inhibited growth of the reil1-1 reil2-1 mutant at 10°C can be rescued by the expression of amino-terminal FLUORESCENT PROTEIN (FP)-REIL fusions driven by the UBIQUITIN10 promoter, allowing the analysis of REIL function in planta. Arabidopsis REIL1 appears to be functionally conserved, based on the cytosolic localization of FP-REIL1 and the interaction of native REIL1 with the 60S subunit in wild-type plants. In contrast to its yeast homologs, REIL1 also was present in translating ribosome fractions. Systems analysis revealed that wild-type Arabidopsis remodels the cytosolic translation machinery when grown at 10°C by accumulating cytosolic ribosome subunits and inducing the expression of cytosolic ribosomal RNA, ribosomal genes, ribosome biogenesis factors, and translation initiation or elongation factors. In the reil1-1 reil2-1 mutant, all processes associated with inhibited growth were delayed, although the plants maintained cellular integrity or acquired freezing tolerance. REIL proteins also were implicated in plant-specific processes: nonacclimated reil1-1 reil2-1 exhibited cold-acclimation responses, including activation of the DREB/CBF regulon. In addition, acclimated reil1-1 reil2-1 plants failed to activate FLOWERING LOCUS T expression in mature leaves. Therefore, in the wild type, REIL function may contribute to temperature perception by suppressing premature cold responses during growth at nonstressful temperatures. In conclusion, we suggest that Arabidopsis REIL proteins influence cold-induced plant ribosome remodeling and enhance the accumulation of cytosolic ribosome subunits after cold shift either by de novo synthesis or by recycling them from the translating ribosome fraction.

Disulfide driven folding for a conditionally disordered protein

Conditionally disordered proteins are either ordered or disordered depending on the environmental context. The substrates of the mitochondrial intermembrane space (IMS) oxidoreductase Mia40 are synthesized on cytosolic ribosomes and diffuse as intrinsically disordered proteins to the IMS, where they fold into their functional conformations; behaving thus as conditionally disordered proteins. It is not clear how the sequences of these polypeptides encode at the same time for their ability to adopt a folded structure and to remain unfolded. Here we characterize the disorder-to-order transition of a Mia40 substrate, the human small copper chaperone Cox17. Using an integrated real-time approach, including chromatography, fluorescence, CD, FTIR, SAXS, NMR, and MS analysis, we demonstrate that in this mitochondrial protein, the conformational switch between disordered and folded states is controlled by the formation of a single disulfide bond, both in the presence and in the absence of Mia40. We provide molecular details on how the folding of a conditionally disordered protein is tightly regulated in time and space, in such a way that the same sequence is competent for protein translocation and activity.

Vms1: A Cytosolic CAT-Tailing Antagonist to Protect Mitochondria.

In eukaryotes, a cytosolic ribosome quality control complex recycles erroneously stalled ribosomes and modifies faulty nascent chains by ubiquitination and by C-terminal Ala- and Thr-extension (CAT-tailing). Reported recently in Cell, Izawa et al. identify cytosolic Vms1 (VCP/Cdc48-associated mitochondrial stress-responsive 1) as an inhibitor of CAT-tailing, which prevents mitochondrial dysfunction caused by imported CAT-tailed polypeptides.

Balance between Cytosolic and Chloroplast Translation Affects Leaf Variegation.

The development of functional chloroplasts relies on the fine coordination of expressions of both nuclear and chloroplast genomes. We have been using the Arabidopsis (Arabidopsis thaliana) yellow variegated (var2) leaf variegation mutant as a tool to dissect the regulation of chloroplast development. In this work, we screened for var2 genetic enhancer modifiers termed enhancer of variegation (evr) mutants and report the characterization of the first EVR locus, EVR1 We showed that EVR1 encodes the cytosolic 80S ribosome 40S small subunit protein RPS21B and the loss of EVR1 causes the enhancement of var2 leaf variegation. We further demonstrated that combined S21 activities from EVR1 and its close homolog, EVR1L1, are essential for Arabidopsis, and they act redundantly in regulating leaf development and var2 leaf variegation. Moreover, using additional cytosolic ribosomal protein mutants, we showed that although mutations in cytosolic ribosomal proteins all enhance var2 leaf variegation to varying degrees, the 40S subunit appears to have a more profound role over the 60S subunit in regulating VAR2-mediated chloroplast development. Comprehensive genetic analyses with var2 suppressors that are defective in chloroplast translation established that the enhancement of var2 leaf variegation by cytosolic ribosomal protein mutants is dependent on chloroplast translation. Based on our data, we propose a model that incorporates the suppression and enhancement of var2 leaf variegation, and hypothesize that VAR2/AtFtsH2 may be intimately involved in the balancing of cytosolic and chloroplast translation programs during chloroplast biogenesis.

19 - Importing of peroxiredoxins to distinct mitochondrial compartments: possible impacts on physiology and pathology

Peroxiredoxin (Prx) enzymes are considered major systems for reduction of peroxides in mitochondria. Although the import of Prx from cytosolic ribosomes to distinct mitochondrial subcompartments is driven by a cleavable N-terminal presequence, the mechanisms underlying this process are still elusive. Here, we show by cell fractionation/western blot analysis that yeast mitochondrial Prx (Prx1) displays dual localization: matrix and intermembrane space. Prx1 sorting into the intermembrane space likely involves the release of the precursor protein within the lipid bilayer of the inner membrane, followed by cleavage by the inner membrane peptidase complex (IMP). Alternatively, during its translocation into the matrix, Prx1 is sequentially cleaved by mitochondrial processing peptidase (MPP) and then by octapeptidyl aminopeptidase 1 (Oct1). Oct1 removed eight amino acid residues from the N-terminal region of Prx1, but its physiological role is still elusive. Remarkably, the processing of Prx proteins by Oct1 appears to be evolutionarily conserved, since yeast Oct1 could also cleave the human mitochondrial peroxiredoxin Prx3 when this thiol peroxidase was expressed in yeast. In addition, the alignment of the N-terminal amino acid sequences of Prx3 from mammals indicated the putative cleavage sites by MPP and Oct1 proteases. Remarkably, there are orthologues of IMP and Oct1 proteins in human cells and their malfunctioning was associated with diseases. For instance, loss of Oct1 provokes disturbances in iron metabolism and loss of mitochondrial DNA. Currently, we are investigating the import of mammalian Prx enzymes into distinct mitochondrial subcompartments and the involvement of IMP and Oct1orthologues.

Cytosolic Protein Vms1 Links Ribosome Quality Control to Mitochondrial and Cellular Homeostasis

Eukaryotic cells have evolved extensive protein quality-control mechanisms to remove faulty translation products. Here, we show that yeast cells continually produce faulty mitochondrial polypeptides that stall on the ribosome during translation but are imported into the mitochondria. The cytosolic protein Vms1, together with the E3 ligase Ltn1, protects against the mitochondrial toxicity of these proteins and maintains cell viability under respiratory conditions. In the absence of these factors, stalled polypeptides aggregate after import and sequester critical mitochondrial chaperone and translation machinery. Aggregation depends on C-terminal alanyl/threonyl sequences (CAT-tails) that are attached to stalled polypeptides on 60S ribosomes by Rqc2. Vms1 binds to 60S ribosomes at the mitochondrial surface and antagonizes Rqc2, thereby facilitating import, impeding aggregation, and directing aberrant polypeptides to intra-mitochondrial quality control. Vms1 is a key component of a rescue pathway for ribosome-stalled mitochondrial polypeptides that are inaccessible to ubiquitylation due to coupling of translation and translocation.

Proteolytic cleavage by the inner membrane peptidase (IMP) complex or Oct1 peptidase controls the localization of the yeast peroxiredoxin Prx1 to distinct mitochondrial compartments

Yeast Prx1 is a mitochondrial 1-Cys peroxiredoxin that catalyzes the reduction of endogenously generated H2O2 Prx1 is synthesized on cytosolic ribosomes as a preprotein with a cleavable N-terminal presequence that is the mitochondrial targeting signal, but the mechanisms underlying Prx1 distribution to distinct mitochondrial subcompartments are unknown. Here, we provide direct evidence of the following dual mitochondrial localization of Prx1: a soluble form in the intermembrane space and a form in the matrix weakly associated with the inner mitochondrial membrane. We show that Prx1 sorting into the intermembrane space likely involves the release of the protein precursor within the lipid bilayer of the inner membrane, followed by cleavage by the inner membrane peptidase. We also found that during its import into the matrix compartment, Prx1 is sequentially cleaved by mitochondrial processing peptidase and then by octapeptidyl aminopeptidase 1 (Oct1). Oct1 cleaved eight amino acid residues from the N-terminal region of Prx1 inside the matrix, without interfering with its peroxidase activity in vitro Remarkably, the processing of peroxiredoxin (Prx) proteins by Oct1 appears to be an evolutionarily conserved process because yeast Oct1 could cleave the human mitochondrial peroxiredoxin Prx3 when expressed in Saccharomyces cerevisiae Altogether, the processing of peroxiredoxins by Imp2 or Oct1 likely represents systems that control the localization of Prxs into distinct compartments and thereby contribute to various mitochondrial redox processes.

ASPM and CITK regulate spindle orientation by affecting the dynamics of astral microtubules.

Corrigendum2 October 2017free access ASPM and CITK regulate spindle orientation by affecting the dynamics of astral microtubules Marta Gai Search for more papers by this author Federico T Bianchi Search for more papers by this author Cristiana Vagnoni Search for more papers by this author Fiammetta Vernì Search for more papers by this author Silvia Bonaccorsi Search for more papers by this author Selina Pasquero Search for more papers by this author Gaia E Berto Search for more papers by this author Francesco Sgrò Search for more papers by this author Alessandra A Chiotto Search for more papers by this author Laura Annaratone Search for more papers by this author Anna Sapino Search for more papers by this author Anna Bergo Search for more papers by this author Nicoletta Landsberger orcid.org/0000-0003-0820-3155 Search for more papers by this author Jacqueline Bond Search for more papers by this author Wieland B Huttner orcid.org/0000-0003-4143-7201 Search for more papers by this author Ferdinando Di Cunto orcid.org/0000-0001-9367-6357 Search for more papers by this author Marta Gai Search for more papers by this author Federico T Bianchi Search for more papers by this author Cristiana Vagnoni Search for more papers by this author Fiammetta Vernì Search for more papers by this author Silvia Bonaccorsi Search for more papers by this author Selina Pasquero Search for more papers by this author Gaia E Berto Search for more papers by this author Francesco Sgrò Search for more papers by this author Alessandra A Chiotto Search for more papers by this author Laura Annaratone Search for more papers by this author Anna Sapino Search for more papers by this author Anna Bergo Search for more papers by this author Nicoletta Landsberger orcid.org/0000-0003-0820-3155 Search for more papers by this author Jacqueline Bond Search for more papers by this author Wieland B Huttner orcid.org/0000-0003-4143-7201 Search for more papers by this author Ferdinando Di Cunto orcid.org/0000-0001-9367-6357 Search for more papers by this author Author Information Marta Gai, Federico T Bianchi, Cristiana Vagnoni, Fiammetta Vernì, Silvia Bonaccorsi, Selina Pasquero, Gaia E Berto, Francesco Sgrò, Alessandra A Chiotto, Laura Annaratone, Anna Sapino, Anna Bergo, Nicoletta Landsberger, Jacqueline Bond, Wieland B Huttner and Ferdinando Di Cunto EMBO Rep (2017)18:1870-1870https://doi.org/10.15252/embr.201745023 This article corrects the following: ASPM and CITK regulate spindle orientation by affecting the dynamics of astral microtubules25 August 2016 PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info The affiliations of Anna Bergo, Nicoletta Landsberger and Anna Sapino were listed incorrectly. The authors have confirmed that the correct affiliation for AB is the “Department of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio, Italy” and that AB was never affiliated with the “San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy”. In addition to the “San Raffaele Rett Research Unit”, NL is also affiliated with the “Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Italy”. In addition to the “Department of Medical Sciences, University of Turin”, AS is also affiliated with “Candiolo Cancer Institute-FPO, IRCCS, Candiolo Turin, Italy”. The authors apologise for any inconvenience caused. Next ArticlePrevious Article Read MoreAbout the coverClose modalView large imageVolume 18,Issue 10,October 2017Cover: Mitochondrial proteins are synthesised in the cytosol by soluble and mitochondria‐bound ribosomes. By electron cryo‐tomography, the clustered organisation of translating ribosomes is revealed on the mitochondrial outer membrane, depicting the spatial distribution of protein import sites. From Vicki AM Gold, Piotr Chroscicki, Piotr Bragoszewski and Agnieszka Chacinska: Visualization of cytosolic ribosomes on the surface of mitochondria by electron cryo‐tomography. For detail, see Article on page 1786. Cover design by Dr Vicki AM Gold, University of Exeter Volume 18Issue 101 October 2017In this issue RelatedDetailsLoading ...

Mcp3 is a novel mitochondrial outer membrane protein that follows a unique IMP-dependent biogenesis pathway.

Corrigendum2 October 2017free access Mcp3 is a novel mitochondrial outer membrane protein that follows a unique IMP-dependent biogenesis pathway Monika Sinzel Search for more papers by this author Tao Tan Search for more papers by this author Philipp Wendling Search for more papers by this author Hubert Kalbacher Search for more papers by this author Cagakan Özbalci Search for more papers by this author Xenia Chelius Search for more papers by this author Benedikt Westermann Search for more papers by this author Britta Brügger Search for more papers by this author Doron Rapaport Search for more papers by this author Kai Stefan Dimmer orcid.org/0000-0003-4535-5115 Search for more papers by this author Monika Sinzel Search for more papers by this author Tao Tan Search for more papers by this author Philipp Wendling Search for more papers by this author Hubert Kalbacher Search for more papers by this author Cagakan Özbalci Search for more papers by this author Xenia Chelius Search for more papers by this author Benedikt Westermann Search for more papers by this author Britta Brügger Search for more papers by this author Doron Rapaport Search for more papers by this author Kai Stefan Dimmer orcid.org/0000-0003-4535-5115 Search for more papers by this author Author Information Monika Sinzel, Tao Tan, Philipp Wendling, Hubert Kalbacher, Cagakan Özbalci, Xenia Chelius, Benedikt Westermann, Britta Brügger, Doron Rapaport and Kai Stefan Dimmer EMBO Rep (2017)18:1869-1869https://doi.org/10.15252/embr.201745020 This article corrects the following: Mcp3 is a novel mitochondrial outer membrane protein that follows a unique IMP-dependent biogenesis pathway25 May 2016 PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info The authors noticed an error in Appendix Fig S1 as follows: In the original publication, we show the same panel for SG-Leu medium at both 30°C and 37°C, although this panel represents only 30°C, and another panel should have been shown for 37°C. In the corrected Appendix Fig S1, we fixed this error and present the correct panel for 37°C. This mistake does not alter the scientific conclusion from this figure, namely that the over-expression of Mcp3 does not influence the growth of yeast cells under these conditions. We would like to apologize for this mistake and any inconvenience it may have caused. Appendix Figure S1. Previous ArticleNext Article Read MoreAbout the coverClose modalView large imageVolume 18,Issue 10,October 2017Cover: Mitochondrial proteins are synthesised in the cytosol by soluble and mitochondria‐bound ribosomes. By electron cryo‐tomography, the clustered organisation of translating ribosomes is revealed on the mitochondrial outer membrane, depicting the spatial distribution of protein import sites. From Vicki AM Gold, Piotr Chroscicki, Piotr Bragoszewski and Agnieszka Chacinska: Visualization of cytosolic ribosomes on the surface of mitochondria by electron cryo‐tomography. For detail, see Article on page 1786. Cover design by Dr Vicki AM Gold, University of Exeter Volume 18Issue 101 October 2017In this issue RelatedDetailsLoading ...