1
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Farkas Á, Urlaub H, Bohnsack KE, Schwappach B. Regulated targeting of the monotopic hairpin membrane protein Erg1 requires the GET pathway. J Biophys Biochem Cytol 2022; 221:213228. [PMID: 35587358 PMCID: PMC9123286 DOI: 10.1083/jcb.202201036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/27/2022] [Accepted: 04/12/2022] [Indexed: 02/08/2023] Open
Abstract
The guided entry of tail-anchored proteins (GET) pathway targets C-terminally anchored transmembrane proteins and protects cells from lipotoxicity. Here, we reveal perturbed ergosterol production in ∆get3 cells and demonstrate the sensitivity of GET pathway mutants to the sterol synthesis inhibiting drug terbinafine. Our data uncover a key enzyme of sterol synthesis, the hairpin membrane protein squalene monooxygenase (Erg1), as a non-canonical GET pathway client, thus rationalizing the lipotoxicity phenotypes of GET pathway mutants. Get3 recognizes the hairpin targeting element of Erg1 via its classical client-binding pocket. Intriguingly, we find that the GET pathway is especially important for the acute upregulation of Erg1 induced by low sterol conditions. We further identify several other proteins anchored to the endoplasmic reticulum (ER) membrane exclusively via a hairpin as putative clients of the GET pathway. Our findings emphasize the necessity of dedicated targeting pathways for high-efficiency targeting of particular clients during dynamic cellular adaptation and highlight hairpin proteins as a potential novel class of GET clients.
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Affiliation(s)
- Ákos Farkas
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytic Mass Spectrometry, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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2
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Takeuchi H, Yamamoto M, Fukui M, Inoue A, Maezawa T, Nishioka M, Kondo E, Ikeda T, Matsumoto K, Miyamoto K. Single‐cell profiling of transcriptomic changes during
in vitro
maturation of human oocytes. Reprod Med Biol 2022; 21:e12464. [PMID: 35582522 PMCID: PMC9084694 DOI: 10.1002/rmb2.12464] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose In vitro maturation (IVM) of human oocytes offers an invaluable opportunity for infertility treatment. However, in vitro matured oocytes often show lower developmental abilities than their in vivo counterparts, and molecular mechanisms underlying successful maturation remain unclear. In this study, we investigated gene expression profiles of in vitro matured oocytes at the single‐cell level to gain mechanistic insight into IVM of human oocytes. Methods Human oocytes were retrieved by follicular puncture and in vitro matured. In total, 19 oocytes from 11 patients were collected and subjected to single‐cell RNA‐seq analyses. Results Global gene expression profiles were similar among oocytes at the same maturation stage, while a small number of oocytes showed distinct transcriptomes from those at the corresponding maturation stage. Differential gene expression analysis identified hundreds of transcripts that dynamically altered their expression during IVM, and we revealed molecular pathways and upstream regulators that may govern oocyte maturation. Furthermore, oocytes that were delayed in their maturation showed distinct transcriptomes. Finally, we identified genes whose transcripts were enriched in each stage of oocyte maturation. Conclusions Our work uncovers transcriptomic changes during human oocyte IVM and the differential gene expression profile of each oocyte.
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Affiliation(s)
- Hiroki Takeuchi
- Department of Obstetrics and Gynecology Graduate School of Medicine Mie University Mie Japan
| | - Mari Yamamoto
- Graduate School of Biology‐Oriented Science and Technology Kindai University Wakayama Japan
| | - Megumi Fukui
- Department of Obstetrics and Gynecology Graduate School of Medicine Mie University Mie Japan
| | - Akihiro Inoue
- Graduate School of Biology‐Oriented Science and Technology Kindai University Wakayama Japan
| | - Tadashi Maezawa
- Department of Obstetrics and Gynecology Graduate School of Medicine Mie University Mie Japan
| | - Mikiko Nishioka
- Department of Obstetrics and Gynecology Graduate School of Medicine Mie University Mie Japan
| | - Eiji Kondo
- Department of Obstetrics and Gynecology Graduate School of Medicine Mie University Mie Japan
| | - Tomoaki Ikeda
- Department of Obstetrics and Gynecology Graduate School of Medicine Mie University Mie Japan
| | - Kazuya Matsumoto
- Graduate School of Biology‐Oriented Science and Technology Kindai University Wakayama Japan
| | - Kei Miyamoto
- Graduate School of Biology‐Oriented Science and Technology Kindai University Wakayama Japan
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3
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Tirincsi A, Sicking M, Hadzibeganovic D, Haßdenteufel S, Lang S. The Molecular Biodiversity of Protein Targeting and Protein Transport Related to the Endoplasmic Reticulum. Int J Mol Sci 2021; 23:143. [PMID: 35008565 PMCID: PMC8745461 DOI: 10.3390/ijms23010143] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 12/15/2022] Open
Abstract
Looking at the variety of the thousands of different polypeptides that have been focused on in the research on the endoplasmic reticulum from the last five decades taught us one humble lesson: no one size fits all. Cells use an impressive array of components to enable the safe transport of protein cargo from the cytosolic ribosomes to the endoplasmic reticulum. Safety during the transit is warranted by the interplay of cytosolic chaperones, membrane receptors, and protein translocases that together form functional networks and serve as protein targeting and translocation routes. While two targeting routes to the endoplasmic reticulum, SRP (signal recognition particle) and GET (guided entry of tail-anchored proteins), prefer targeting determinants at the N- and C-terminus of the cargo polypeptide, respectively, the recently discovered SND (SRP-independent) route seems to preferentially cater for cargos with non-generic targeting signals that are less hydrophobic or more distant from the termini. With an emphasis on targeting routes and protein translocases, we will discuss those functional networks that drive efficient protein topogenesis and shed light on their redundant and dynamic nature in health and disease.
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Affiliation(s)
- Andrea Tirincsi
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Mark Sicking
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Drazena Hadzibeganovic
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Sarah Haßdenteufel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sven Lang
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
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4
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Mehlhorn DG, Asseck LY, Grefen C. Looking for a safe haven: tail-anchored proteins and their membrane insertion pathways. PLANT PHYSIOLOGY 2021; 187:1916-1928. [PMID: 35235667 PMCID: PMC8644595 DOI: 10.1093/plphys/kiab298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/05/2021] [Indexed: 06/14/2023]
Abstract
Insertion of membrane proteins into the lipid bilayer is a crucial step during their biosynthesis. Eukaryotic cells face many challenges in directing these proteins to their predestined target membrane. The hydrophobic signal peptide or transmembrane domain (TMD) of the nascent protein must be shielded from the aqueous cytosol and its target membrane identified followed by transport and insertion. Components that evolved to deal with each of these challenging steps range from chaperones to receptors, insertases, and sophisticated translocation complexes. One prominent translocation pathway for most proteins is the signal recognition particle (SRP)-dependent pathway which mediates co-translational translocation of proteins across or into the endoplasmic reticulum (ER) membrane. This textbook example of protein insertion is stretched to its limits when faced with secretory or membrane proteins that lack an amino-terminal signal sequence or TMD. Particularly, a large group of so-called tail-anchored (TA) proteins that harbor a single carboxy-terminal TMD require an alternative, post-translational insertion route into the ER membrane. In this review, we summarize the current research in TA protein insertion with a special focus on plants, address challenges, and highlight future research avenues.
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Affiliation(s)
- Dietmar G Mehlhorn
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Lisa Y Asseck
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Christopher Grefen
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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5
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Chio US, Liu Y, Chung S, Shim WJ, Chandrasekar S, Weiss S, Shan SO. Subunit cooperation in the Get1/2 receptor promotes tail-anchored membrane protein insertion. J Cell Biol 2021; 220:212681. [PMID: 34614151 PMCID: PMC8530227 DOI: 10.1083/jcb.202103079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 08/03/2021] [Accepted: 08/19/2021] [Indexed: 11/29/2022] Open
Abstract
The guided entry of tail-anchored protein (GET) pathway, in which the Get3 ATPase delivers an essential class of tail-anchored membrane proteins (TAs) to the Get1/2 receptor at the endoplasmic reticulum, provides a conserved mechanism for TA biogenesis in eukaryotic cells. The membrane-associated events of this pathway remain poorly understood. Here we show that complex assembly between the cytosolic domains (CDs) of Get1 and Get2 strongly enhances the affinity of the individual subunits for Get3•TA, thus enabling efficient capture of the targeting complex. In addition to the known role of Get1CD in remodeling Get3 conformation, two molecular recognition features (MoRFs) in Get2CD induce Get3 opening, and both subunits are required for optimal TA release from Get3. Mutation of the MoRFs attenuates TA insertion into the ER in vivo. Our results demonstrate extensive cooperation between the Get1/2 receptor subunits in the capture and remodeling of the targeting complex, and emphasize the role of MoRFs in receptor function during membrane protein biogenesis.
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Affiliation(s)
- Un Seng Chio
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Yumeng Liu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - SangYoon Chung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA
| | - Woo Jun Shim
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Sowmya Chandrasekar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA.,Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
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6
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Molecular characterization and analysis of the ATPase ASNA1 homolog gene of Eimeria tenella in a drug sensitive strain and drug resistant strains. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2021; 15:115-125. [PMID: 33639573 PMCID: PMC7910411 DOI: 10.1016/j.ijpddr.2021.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 02/03/2021] [Accepted: 02/08/2021] [Indexed: 02/03/2023]
Abstract
The widespread use of drugs has exacerbated the resistance of Eimeria tenalla to anti-coccidial drugs. Using RNA-seq, we previously found the ATPase ASNA1 homolog of E. tenella (EtASNA1) was differentially expressed in resistant strains and drug sensitive (DS) strain. In our study, we used western blotting and quantitative real-time PCR (qRT-PCR) to analyze the translational and transcriptional levels of EtASNA1 in a diclazuril-resistant (DZR) strain, maduramicin-resistant (MRR) strain, salinomycin-resistant (SMR) strain, and DS strain and found EtASNA1 was highly expressed in three drug-resistant strains. The qRT-PCR and western blotting results also showed that the expression levels of EtASNA1 increased with increasing drug concentration, and the transcription levels of the DZR strains isolated from the field were higher than those of the DS strain. In addition, we used in vivo and in vitro tests to analyze the changes of EtASNA1 expression after DZR, MRR, and DS strain infections in chickens, and in vitro inoculation of DF-1 cells in the presence of drugs. The addition of drugs caused expression to be upregulated. The results of qRT-PCR and western blotting also showed that the expression levels of EtASNA1 in second-generation merozoites (SM) and unsporulated oocysts (UO) were significantly higher than those in the other two developmental stages. The immunofluorescence localization of EtASNA1 indicated that the protein was distributed throughout the sporozoites (SZ) and SM, except for the refractile bodies of SZ. In vitro inhibition experiments showed that anti-EtASNA1 antibody incubation significantly inhibited SZ invasion of DF-1 cells. The above results showed that EtASNA1 may be related to host cell invasion of E. tenella and may be involved in the development of E. tenella resistance to some drugs.
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7
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Ulrich K, Schwappach B, Jakob U. Thiol-based switching mechanisms of stress-sensing chaperones. Biol Chem 2020; 402:239-252. [PMID: 32990643 DOI: 10.1515/hsz-2020-0262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 09/11/2020] [Indexed: 12/13/2022]
Abstract
Thiol-based redox switches evolved as efficient post-translational regulatory mechanisms that enable individual proteins to rapidly respond to sudden environmental changes. While some protein functions need to be switched off to save resources and avoid potentially error-prone processes, protective functions become essential and need to be switched on. In this review, we focus on thiol-based activation mechanisms of stress-sensing chaperones. Upon stress exposure, these chaperones convert into high affinity binding platforms for unfolding proteins and protect cells against the accumulation of potentially toxic protein aggregates. Their chaperone activity is independent of ATP, a feature that becomes especially important under oxidative stress conditions, where cellular ATP levels drop and canonical ATP-dependent chaperones no longer operate. Vice versa, reductive inactivation and substrate release require the restoration of ATP levels, which ensures refolding of client proteins by ATP-dependent foldases. We will give an overview over the different strategies that cells evolved to rapidly increase the pool of ATP-independent chaperones upon oxidative stress and provide mechanistic insights into how stress conditions are used to convert abundant cellular proteins into ATP-independent holding chaperones.
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Affiliation(s)
- Kathrin Ulrich
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 1105 N. University Ave., Ann Arbor, MI48109, USA
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Ursula Jakob
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 1105 N. University Ave., Ann Arbor, MI48109, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI48109, USA
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8
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Farkas Á, De Laurentiis EI, Schwappach B. The natural history of Get3-like chaperones. Traffic 2020; 20:311-324. [PMID: 30972921 PMCID: PMC6593721 DOI: 10.1111/tra.12643] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 02/02/2023]
Abstract
Get3 in yeast or TRC40 in mammals is an ATPase that, in eukaryotes, is a central element of the GET or TRC pathway involved in the targeting of tail-anchored proteins. Get3 has also been shown to possess chaperone holdase activity. A bioinformatic assessment was performed across all domains of life on functionally important regions of Get3 including the TRC40-insert and the hydrophobic groove essential for tail-anchored protein binding. We find that such a hydrophobic groove is much more common in bacterial Get3 homologs than previously appreciated based on a directed comparison of bacterial ArsA and yeast Get3. Furthermore, our analysis shows that the region containing the TRC40-insert varies in length and methionine content to an unexpected extent within eukaryotes and also between different phylogenetic groups. In fact, since the TRC40-insert is present in all domains of life, we suggest that its presence does not automatically predict a tail-anchored protein targeting function. This opens up a new perspective on the function of organellar Get3 homologs in plants which feature the TRC40-insert but have not been demonstrated to function in tail-anchored protein targeting. Our analysis also highlights a large diversity of the ways Get3 homologs dimerize. Thus, based on the structural features of Get3 homologs, these proteins may have an unexplored functional diversity in all domains of life.
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Affiliation(s)
- Ákos Farkas
- Department of Molecular Biology, Göttingen University Medical Center, Göttingen, Germany
| | | | - Blanche Schwappach
- Department of Molecular Biology, Göttingen University Medical Center, Göttingen, Germany.,Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
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9
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Abstract
Due to their topology tail-anchored (TA) proteins must target to the membrane independently of the co-translational route defined by the signal sequence recognition particle (SRP), its receptor and the translocon Sec61. More than a decade of work has extensively characterized a highly conserved pathway, the yeast GET or mammalian TRC40 pathway, which is capable of countering the biogenetic challenge posed by the C-terminal TA anchor. In this review we briefly summarize current models of this targeting route and focus on emerging aspects such as the intricate interplay with the proteostatic network of cells and with other targeting pathways. Importantly, we consider the lessons provided by the in vivo analysis of the pathway in different model organisms and by the consideration of its full client spectrum in more recent studies. This analysis of the state of the field highlights directions in which the current models may be experimentally probed and conceptually extended.
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Affiliation(s)
- Nica Borgese
- Institute of Neuroscience and BIOMETRA Department, Consiglio Nazionale delle Ricerche and Università degli Studi di Milano, via Vanvitelli 32, 20129, Milan, Italy.
| | - Javier Coy-Vergara
- Department of Molecular Biology, University of Göttingen Medical Centre, Humboldtallee 23, 37073, Göttingen, Germany
| | - Sara Francesca Colombo
- Institute of Neuroscience and BIOMETRA Department, Consiglio Nazionale delle Ricerche and Università degli Studi di Milano, via Vanvitelli 32, 20129, Milan, Italy
| | - Blanche Schwappach
- Department of Molecular Biology, University of Göttingen Medical Centre, Humboldtallee 23, 37073, Göttingen, Germany.
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10
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Verhagen JMA, van den Born M, van der Linde HC, G J Nikkels P, Verdijk RM, Kivlen MH, van Unen LMA, Baas AF, Ter Heide H, van Osch-Gevers L, Hoogeveen-Westerveld M, Herkert JC, Bertoli-Avella AM, van Slegtenhorst MA, Wessels MW, Verheijen FW, Hassel D, Hofstra RMW, Hegde RS, van Hasselt PM, van Ham TJ, van de Laar IMBH. Biallelic Variants in ASNA1, Encoding a Cytosolic Targeting Factor of Tail-Anchored Proteins, Cause Rapidly Progressive Pediatric Cardiomyopathy. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 12:397-406. [PMID: 31461301 PMCID: PMC7205403 DOI: 10.1161/circgen.119.002507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Pediatric cardiomyopathies are a clinically and genetically heterogeneous group of heart muscle disorders associated with high morbidity and mortality. Although knowledge of the genetic basis of pediatric cardiomyopathy has improved considerably, the underlying cause remains elusive in a substantial proportion of cases.
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Affiliation(s)
- Judith M A Verhagen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Myrthe van den Born
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Herma C van der Linde
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Peter G J Nikkels
- Department of Pathology (P.G.J.N.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Rob M Verdijk
- Department of Pathology (R.M.V.), Erasmus MC, University Medical Center Rotterdam
| | - Maryann H Kivlen
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, United Kingdom (M.H.K., R.S.H.)
| | - Leontine M A van Unen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Annette F Baas
- Department of Genetics (A.F.B.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Henriette Ter Heide
- Department of Pediatric Cardiology (H.t.H.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Lennie van Osch-Gevers
- Department of Pediatric Cardiology (L.v.O.-G.), Erasmus MC, University Medical Center Rotterdam
| | - Marianne Hoogeveen-Westerveld
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Johanna C Herkert
- Department of Genetics, University of Groningen, University Medical Center Groningen, the Netherlands (J.C.H.)
| | | | - Marjon A van Slegtenhorst
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Marja W Wessels
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Frans W Verheijen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - David Hassel
- Department of Medicine III, University Hospital Heidelberg, Germany (D.H.)
| | - Robert M W Hofstra
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Ramanujan S Hegde
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, United Kingdom (M.H.K., R.S.H.)
| | - Peter M van Hasselt
- Department of Pediatrics (P.M.v.H.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
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11
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Lin TW, Chen CC, Wu SM, Chang YC, Li YC, Su YW, Hsiao CD, Chang HY. Structural analysis of chloroplast tail-anchored membrane protein recognition by ArsA1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:128-143. [PMID: 30891827 DOI: 10.1111/tpj.14316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/26/2019] [Accepted: 03/11/2019] [Indexed: 06/09/2023]
Abstract
In mammals and yeast, tail-anchored (TA) membrane proteins destined for the post-translational pathway are safely delivered to the endoplasmic reticulum (ER) membrane by a well-known targeting factor, TRC40/Get3. In contrast, the underlying mechanism for translocation of TA proteins in plants remains obscure. How this unique eukaryotic membrane-trafficking system correctly distinguishes different subsets of TA proteins destined for various organelles, including mitochondria, chloroplasts and the ER, is a key question of long standing. Here, we present crystal structures of algal ArsA1 (the Get3 homolog) in a distinct nucleotide-free open state and bound to adenylyl-imidodiphosphate. This approximately 80-kDa protein possesses a monomeric architecture, with two ATPase domains in a single polypeptide chain. It is capable of binding chloroplast (TOC34 and TOC159) and mitochondrial (TOM7) TA proteins based on features of its transmembrane domain as well as the regions immediately before and after the transmembrane domain. Several helices located above the TA-binding groove comprise the interlocking hook-like motif implicated by mutational analyses in TA substrate recognition. Our data provide insights into the molecular basis of the highly specific selectivity of interactions of algal ArsA1 with the correct sets of TA substrates before membrane targeting in plant cells.
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Affiliation(s)
- Tai-Wen Lin
- Molecular and Cell Biology, International Graduate Program, Academia Sinica and Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
| | - Chi-Chih Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
- The Asia-Pacific Ocean Research Center, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
- Doctoral Degree Program in Marine Biotechnology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, 70 Lien-Hai Road, Kaohsiung, 80424, Taiwan
| | - Shu-Mei Wu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Yu-Ching Chang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Yi-Chuan Li
- Molecular and Cell Biology, International Graduate Program, Academia Sinica and Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan
| | - Yu-Wang Su
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Chwan-Deng Hsiao
- Molecular and Cell Biology, International Graduate Program, Academia Sinica and Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
- Doctoral Degree Program in Marine Biotechnology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
| | - Hsin-Yang Chang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
- The Asia-Pacific Ocean Research Center, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, 70 Lien-Hai Road, Kaohsiung, 80424, Taiwan
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12
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Coy-Vergara J, Rivera-Monroy J, Urlaub H, Lenz C, Schwappach B. A trap mutant reveals the physiological client spectrum of TRC40. J Cell Sci 2019; 132:jcs.230094. [PMID: 31182645 PMCID: PMC6633398 DOI: 10.1242/jcs.230094] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/31/2019] [Indexed: 12/13/2022] Open
Abstract
The transmembrane recognition complex (TRC) pathway targets tail-anchored (TA) proteins to the membrane of the endoplasmic reticulum (ER). While many TA proteins are known to be able to use this pathway, it is essential for the targeting of only a few. Here, we uncover a large number of TA proteins that engage with TRC40 when other targeting machineries are fully operational. We use a dominant-negative ATPase-impaired mutant of TRC40 in which aspartate 74 was replaced by a glutamate residue to trap TA proteins in the cytoplasm. Manipulation of the hydrophobic TA-binding groove in TRC40 (also known as ASNA1) reduces interaction with most, but not all, substrates suggesting that co-purification may also reflect interactions unrelated to precursor protein targeting. We confirm known TRC40 substrates and identify many additional TA proteins interacting with TRC40. By using the trap approach in combination with quantitative mass spectrometry, we show that Golgi-resident TA proteins such as the golgins golgin-84, CASP and giantin as well as the vesicle-associated membrane-protein-associated proteins VAPA and VAPB interact with TRC40. Thus, our results provide new avenues to assess the essential role of TRC40 in metazoan organisms. This article has an associated First Person interview with the first author of the paper. Summary: A strategy to decipher which tail-anchored proteins do (as opposed to can or must) use the TRC pathway in intact cells generates a comprehensive list of human TRC40 clients.
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Affiliation(s)
- Javier Coy-Vergara
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany
| | - Jhon Rivera-Monroy
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen 37077, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen 37077, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany .,Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
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13
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Casson J, McKenna M, Haßdenteufel S, Aviram N, Zimmerman R, High S. Multiple pathways facilitate the biogenesis of mammalian tail-anchored proteins. J Cell Sci 2017; 130:3851-3861. [PMID: 29021347 PMCID: PMC5702047 DOI: 10.1242/jcs.207829] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/17/2017] [Indexed: 12/24/2022] Open
Abstract
Tail-anchored (TA) proteins are transmembrane proteins with a single C-terminal transmembrane domain, which functions as both their subcellular targeting signal and membrane anchor. We show that knockout of TRC40 in cultured human cells has a relatively minor effect on endogenous TA proteins, despite their apparent reliance on this pathway in vitro. These findings support recent evidence that the canonical TRC40 pathway is not essential for TA protein biogenesis in vivo. We therefore investigated the possibility that other ER-targeting routes can complement the TRC40 pathway and identified roles for both the SRP pathway and the recently described mammalian SND pathway in TA protein biogenesis. We conclude that, although TRC40 normally plays an important role in TA protein biogenesis, it is not essential, and speculate that alternative pathways for TA protein biogenesis, including those identified in this study, contribute to the redundancy of the TRC40 pathway. Summary: In addition to the canonical TRC40-targeting pathway, mammalian tail-anchored proteins can also utilise the SRP and SND pathways to facilitate their insertion into the ER membrane.
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Affiliation(s)
- Joseph Casson
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Manchester, M13 9PT, UK
| | - Michael McKenna
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Manchester, M13 9PT, UK
| | - Sarah Haßdenteufel
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Naama Aviram
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Richard Zimmerman
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Stephen High
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Manchester, M13 9PT, UK
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14
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Voth W, Jakob U. Stress-Activated Chaperones: A First Line of Defense. Trends Biochem Sci 2017; 42:899-913. [PMID: 28893460 DOI: 10.1016/j.tibs.2017.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 10/18/2022]
Abstract
Proteins are constantly challenged by environmental stress conditions that threaten their structure and function. Especially problematic are oxidative, acid, and severe heat stress which induce very rapid and widespread protein unfolding and generate conditions that make canonical chaperones and/or transcriptional responses inadequate to protect the proteome. We review here recent advances in identifying and characterizing stress-activated chaperones which are inactive under non-stress conditions but become potent chaperones under specific protein-unfolding stress conditions. We discuss the post-translational mechanisms by which these chaperones sense stress, and consider the role that intrinsic disorder plays in their regulation and function. We examine their physiological roles under both non-stress and stress conditions, their integration into the cellular proteostasis network, and their potential as novel therapeutic targets.
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Affiliation(s)
- Wilhelm Voth
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular Biology, Universitätsmedizin Göttingen, 37073 Göttingen, Germany
| | - Ursula Jakob
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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15
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Daniele LL, Emran F, Lobo GP, Gaivin RJ, Perkins BD. Mutation of wrb, a Component of the Guided Entry of Tail-Anchored Protein Pathway, Disrupts Photoreceptor Synapse Structure and Function. Invest Ophthalmol Vis Sci 2017; 57:2942-54. [PMID: 27273592 PMCID: PMC4898200 DOI: 10.1167/iovs.15-18996] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Tail-anchored (TA) proteins contain a single hydrophobic domain at the C-terminus and are posttranslationally inserted into the ER membrane via the GET (guided entry of tail-anchored proteins) pathway. The role of the GET pathway in photoreceptors is unexplored. The goal of this study was to characterize the zebrafish pinball wizard mutant, which disrupts Wrb, a core component of the GET pathway. METHODS Electroretinography, optokinetic response measurements (OKR), immunohistochemistry, and electron microscopy analyses were employed to assess ribbon synapse function, protein expression, and ultrastructure in 5-day-old zebrafish larvae. Expression of wrb was investigated with real-time qRT-PCR and in situ hybridization. RESULTS Mutation of wrb abolished the OKR and greatly diminished the ERG b-wave, but not the a-wave. Ribeye and SV2 were partially mislocalized in both photoreceptors and hair cells of wrb mutants. Fewer contacts were seen between photoreceptors and bipolar cells in wrb-/- mutants. Expression of wrb was observed throughout the nervous system and Wrb localized to the ER and synaptic region of photoreceptors. Morpholino knockdown of the cytosolic ATPase trc40, which targets TA proteins to the ER, also diminished the OKR. Overexpression of wrb fully restored contrast sensitivity in mutants, while overexpression of mutant wrbR73A, which cannot bind Trc40, did not. CONCLUSIONS Proteins Wrb and Trc40 are required for synaptic transmission between photoreceptors and bipolar cells, indicating that TA protein insertion by the TRC pathway is a critical step in ribbon synapse assembly and function.
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Affiliation(s)
- Lauren L Daniele
- Department of Ophthalmic Research Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Farida Emran
- Centre for Research in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Glenn P Lobo
- Department of Ophthalmic Research Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Robert J Gaivin
- Department of Ophthalmic Research Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Brian D Perkins
- Department of Ophthalmic Research Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
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16
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Maestre-Reyna M, Wu SM, Chang YC, Chen CC, Maestre-Reyna A, Wang AHJ, Chang HY. In search of tail-anchored protein machinery in plants: reevaluating the role of arsenite transporters. Sci Rep 2017; 7:46022. [PMID: 28382961 PMCID: PMC5382584 DOI: 10.1038/srep46022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 03/07/2017] [Indexed: 11/09/2022] Open
Abstract
Although the mechanisms underlying selective targeting of tail-anchored (TA) membrane proteins are well established in mammalian and yeast cells, little is known about their role in mediating intracellular membrane trafficking in plant cells. However, a recent study suggested that, in green algae, arsenite transporters located in the cytosol (ArsA1 and ArsA2) control the insertion of TA proteins into the membrane-bound organelles. In the present work, we overproduced and purified these hydrophilic proteins to near homogeneity. The analysis of their catalytic properties clearly demonstrates that C. reinhardtii ArsA proteins exhibit oxyanion-independent ATPase activity, as neither arsenite nor antimonite showed strong effects. Co-expression of ArsA proteins with TA-transmembrane regions showed not only that the former interact with the latter, but that ArsA1 does not share the same ligand specificity as ArsA2. Together with a structural model and molecular dynamics simulations, we propose that C. reinhadtii ArsA proteins are not arsenite transporters, but a TA-protein targeting factor. Further, we propose that ArsA targeting specificity is achieved at the ligand level, with ArsA1 mainly carrying TA-proteins to the chloroplast, while ArsA2 to the endoplasmic reticulum.
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Affiliation(s)
| | - Shu-Mei Wu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Yu-Ching Chang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Chi-Chih Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, 70 Lien-Hai Road, Kaohsiung 80424, Taiwan
- Doctoral Degree Program in Marine Biotechnology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Alvaro Maestre-Reyna
- Escuela Tecnica Superior de Ingenierios Industriales, Universidad Politecnica de Valencia, Valencia, Spain
| | - Andrew H.-J. Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Core Facilities for Protein Structural Analysis, Academia Sinica, Taipei, Taiwan
- PhD Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Hsin-Yang Chang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, 70 Lien-Hai Road, Kaohsiung 80424, Taiwan
- The Asia-Pacific Ocean Research Center, National Sun Yat-sen University, Kaohsiung 804, Taiwan
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17
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Xing S, Mehlhorn DG, Wallmeroth N, Asseck LY, Kar R, Voss A, Denninger P, Schmidt VAF, Schwarzländer M, Stierhof YD, Grossmann G, Grefen C. Loss of GET pathway orthologs in Arabidopsis thaliana causes root hair growth defects and affects SNARE abundance. Proc Natl Acad Sci U S A 2017; 114:E1544-E1553. [PMID: 28096354 PMCID: PMC5338382 DOI: 10.1073/pnas.1619525114] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are key players in cellular trafficking and coordinate vital cellular processes, such as cytokinesis, pathogen defense, and ion transport regulation. With few exceptions, SNAREs are tail-anchored (TA) proteins, bearing a C-terminal hydrophobic domain that is essential for their membrane integration. Recently, the Guided Entry of Tail-anchored proteins (GET) pathway was described in mammalian and yeast cells that serve as a blueprint of TA protein insertion [Schuldiner M, et al. (2008) Cell 134(4):634-645; Stefanovic S, Hegde RS (2007) Cell 128(6):1147-1159]. This pathway consists of six proteins, with the cytosolic ATPase GET3 chaperoning the newly synthesized TA protein posttranslationally from the ribosome to the endoplasmic reticulum (ER) membrane. Structural and biochemical insights confirmed the potential of pathway components to facilitate membrane insertion, but the physiological significance in multicellular organisms remains to be resolved. Our phylogenetic analysis of 37 GET3 orthologs from 18 different species revealed the presence of two different GET3 clades. We identified and analyzed GET pathway components in Arabidopsis thaliana and found reduced root hair elongation in Atget lines, possibly as a result of reduced SNARE biogenesis. Overexpression of AtGET3a in a receptor knockout (KO) results in severe growth defects, suggesting presence of alternative insertion pathways while highlighting an intricate involvement for the GET pathway in cellular homeostasis of plants.
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Affiliation(s)
- Shuping Xing
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Dietmar Gerald Mehlhorn
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Niklas Wallmeroth
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Lisa Yasmin Asseck
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Ritwika Kar
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Alessa Voss
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Philipp Denninger
- Centre for Organismal Studies, CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Vanessa Aphaia Fiona Schmidt
- Centre for Organismal Studies, CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Markus Schwarzländer
- Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - York-Dieter Stierhof
- Centre for Plant Molecular Biology, Microscopy, University of Tübingen, 72076 Tuebingen, Germany
| | - Guido Grossmann
- Centre for Organismal Studies, CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Christopher Grefen
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany;
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18
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Rivera-Monroy J, Musiol L, Unthan-Fechner K, Farkas Á, Clancy A, Coy-Vergara J, Weill U, Gockel S, Lin SY, Corey DP, Kohl T, Ströbel P, Schuldiner M, Schwappach B, Vilardi F. Mice lacking WRB reveal differential biogenesis requirements of tail-anchored proteins in vivo. Sci Rep 2016; 6:39464. [PMID: 28000760 PMCID: PMC5175141 DOI: 10.1038/srep39464] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/22/2016] [Indexed: 02/06/2023] Open
Abstract
Tail-anchored (TA) proteins are post-translationally inserted into membranes. The TRC40 pathway targets TA proteins to the endoplasmic reticulum via a receptor comprised of WRB and CAML. TRC40 pathway clients have been identified using in vitro assays, however, the relevance of the TRC40 pathway in vivo remains unknown. We followed the fate of TA proteins in two tissue-specific WRB knockout mouse models and found that their dependence on the TRC40 pathway in vitro did not predict their reaction to receptor depletion in vivo. The SNARE syntaxin 5 (Stx5) was extremely sensitive to disruption of the TRC40 pathway. Screening yeast TA proteins with mammalian homologues, we show that the particular sensitivity of Stx5 is conserved, possibly due to aggregation propensity of its cytoplasmic domain. We establish that Stx5 is an autophagy target that is inefficiently membrane-targeted by alternative pathways. Our results highlight an intimate relationship between the TRC40 pathway and cellular proteostasis.
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Affiliation(s)
- Jhon Rivera-Monroy
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Lena Musiol
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Kirsten Unthan-Fechner
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Ákos Farkas
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Anne Clancy
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Javier Coy-Vergara
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Uri Weill
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarah Gockel
- Department of Cardiology &Pulmonology, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
| | - Shuh-Yow Lin
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - David P Corey
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Tobias Kohl
- Department of Cardiology &Pulmonology, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
| | - Philipp Ströbel
- Institute of Pathology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany.,Max-Planck Institute for Biophysical Chemistry, D-37077, Göttingen, Germany
| | - Fabio Vilardi
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
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19
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Vogl C, Panou I, Yamanbaeva G, Wichmann C, Mangosing SJ, Vilardi F, Indzhykulian AA, Pangršič T, Santarelli R, Rodriguez-Ballesteros M, Weber T, Jung S, Cardenas E, Wu X, Wojcik SM, Kwan KY, Del Castillo I, Schwappach B, Strenzke N, Corey DP, Lin SY, Moser T. Tryptophan-rich basic protein (WRB) mediates insertion of the tail-anchored protein otoferlin and is required for hair cell exocytosis and hearing. EMBO J 2016; 35:2536-2552. [PMID: 27458190 DOI: 10.15252/embj.201593565] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/29/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022] Open
Abstract
The transmembrane recognition complex (TRC40) pathway mediates the insertion of tail-anchored (TA) proteins into membranes. Here, we demonstrate that otoferlin, a TA protein essential for hair cell exocytosis, is inserted into the endoplasmic reticulum (ER) via the TRC40 pathway. We mutated the TRC40 receptor tryptophan-rich basic protein (Wrb) in hair cells of zebrafish and mice and studied the impact of defective TA protein insertion. Wrb disruption reduced otoferlin levels in hair cells and impaired hearing, which could be restored in zebrafish by transgenic Wrb rescue and otoferlin overexpression. Wrb-deficient mouse inner hair cells (IHCs) displayed normal numbers of afferent synapses, Ca2+ channels, and membrane-proximal vesicles, but contained fewer ribbon-associated vesicles. Patch-clamp of IHCs revealed impaired synaptic vesicle replenishment. In vivo recordings from postsynaptic spiral ganglion neurons showed a use-dependent reduction in sound-evoked spiking, corroborating the notion of impaired IHC vesicle replenishment. A human mutation affecting the transmembrane domain of otoferlin impaired its ER targeting and caused an auditory synaptopathy. We conclude that the TRC40 pathway is critical for hearing and propose that otoferlin is an essential substrate of this pathway in hair cells.
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Affiliation(s)
- Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Iliana Panou
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Gulnara Yamanbaeva
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Systems Physiology Group and InnerEarLab, Department of Otolaryngology, University of Göttingen Medical Center, Göttingen, Germany
| | - Carolin Wichmann
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sara J Mangosing
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Fabio Vilardi
- Institute of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Artur A Indzhykulian
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Tina Pangršič
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Synaptic Physiology of Mammalian Vestibular Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Rosamaria Santarelli
- Department of Neurosciences, University of Padova, Padova, Italy.,Audiology and Phoniatrics Service, Treviso Regional Hospital, Treviso, Italy
| | | | - Thomas Weber
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sangyong Jung
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Elena Cardenas
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Xudong Wu
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Kelvin Y Kwan
- W. M. Keck Center for Collaborative Neuroscience, Nelson Lab-D250, Rutgers University, Piscataway, NJ, USA
| | - Ignacio Del Castillo
- Servicio de Genetica, Hospital Universitario Ramon y Cajal, IRYCIS, Madrid, Spain.,Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Blanche Schwappach
- Institute of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Nicola Strenzke
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Systems Physiology Group and InnerEarLab, Department of Otolaryngology, University of Göttingen Medical Center, Göttingen, Germany
| | - David P Corey
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Shuh-Yow Lin
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany .,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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20
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Philp LK, Day TK, Butler MS, Laven-Law G, Jindal S, Hickey TE, Scher HI, Butler LM, Tilley WD. Small Glutamine-Rich Tetratricopeptide Repeat-Containing Protein Alpha (SGTA) Ablation Limits Offspring Viability and Growth in Mice. Sci Rep 2016; 6:28950. [PMID: 27358191 PMCID: PMC4928056 DOI: 10.1038/srep28950] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/07/2016] [Indexed: 01/26/2023] Open
Abstract
Small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA) has been implicated as a co-chaperone and regulator of androgen and growth hormone receptor (AR, GHR) signalling. We investigated the functional consequences of partial and full Sgta ablation in vivo using Cre-lox Sgta-null mice. Sgta(+/-) breeders generated viable Sgta(-/-) offspring, but at less than Mendelian expectancy. Sgta(-/-) breeders were subfertile with small litters and higher neonatal death (P < 0.02). Body size was significantly and proportionately smaller in male and female Sgta(-/-) (vs WT, Sgta(+/-) P < 0.001) from d19. Serum IGF-1 levels were genotype- and sex-dependent. Food intake, muscle and bone mass and adiposity were unchanged in Sgta(-/-). Vital and sex organs had normal relative weight, morphology and histology, although certain androgen-sensitive measures such as penis and preputial size, and testis descent, were greater in Sgta(-/-). Expression of AR and its targets remained largely unchanged, although AR localisation was genotype- and tissue-dependent. Generally expression of other TPR-containing proteins was unchanged. In conclusion, this thorough investigation of SGTA-null mutation reports a mild phenotype of reduced body size. The model's full potential likely will be realised by genetic crosses with other models to interrogate the role of SGTA in the many diseases in which it has been implicated.
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Affiliation(s)
- Lisa K. Philp
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | - Tanya K. Day
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | - Miriam S. Butler
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | - Geraldine Laven-Law
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | - Shalini Jindal
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | - Theresa E. Hickey
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | | | - Lisa M. Butler
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
- Freemason’s Foundation Centre for Men’s Health, School of Medicine, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
| | - Wayne D. Tilley
- Adelaide Prostate Cancer Research Centre and Dame Roma Mitchell Cancer Research Laboratories, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
- Freemason’s Foundation Centre for Men’s Health, School of Medicine, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia
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21
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Norlin S, Parekh VS, Naredi P, Edlund H. Asna1/TRC40 Controls β-Cell Function and Endoplasmic Reticulum Homeostasis by Ensuring Retrograde Transport. Diabetes 2016; 65:110-9. [PMID: 26438609 DOI: 10.2337/db15-0699] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/28/2015] [Indexed: 11/13/2022]
Abstract
Type 2 diabetes (T2D) is characterized by insulin resistance and β-cell failure. Insulin resistance per se, however, does not provoke overt diabetes as long as compensatory β-cell function is maintained. The increased demand for insulin stresses the β-cell endoplasmic reticulum (ER) and secretory pathway, and ER stress is associated with β-cell failure in T2D. The tail recognition complex (TRC) pathway, including Asna1/TRC40, is implicated in the maintenance of endomembrane trafficking and ER homeostasis. To gain insight into the role of Asna1/TRC40 in maintaining endomembrane homeostasis and β-cell function, we inactivated Asna1 in β-cells of mice. We show that Asna1(β-/-) mice develop hypoinsulinemia, impaired insulin secretion, and glucose intolerance that rapidly progresses to overt diabetes. Loss of Asna1 function leads to perturbed plasma membrane-to-trans Golgi network and Golgi-to-ER retrograde transport as well as to ER stress in β-cells. Of note, pharmacological inhibition of retrograde transport in isolated islets and insulinoma cells mimicked the phenotype of Asna1(β-/-) β-cells and resulted in reduced insulin content and ER stress. These data support a model where Asna1 ensures retrograde transport and, hence, ER and insulin homeostasis in β-cells.
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Affiliation(s)
- Stefan Norlin
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Vishal S Parekh
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg
| | - Helena Edlund
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
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22
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Differential gradients of interaction affinities drive efficient targeting and recycling in the GET pathway. Proc Natl Acad Sci U S A 2014; 111:E4929-35. [PMID: 25368153 DOI: 10.1073/pnas.1411284111] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Efficient and accurate localization of membrane proteins requires a complex cascade of interactions between protein machineries. This requirement is exemplified in the guided entry of tail-anchored (TA) protein (GET) pathway, where the central targeting factor Get3 must sequentially interact with three distinct binding partners to ensure the delivery of TA proteins to the endoplasmic reticulum (ER) membrane. To understand the molecular principles that provide the vectorial driving force of these interactions, we developed quantitative fluorescence assays to monitor Get3-effector interactions at each stage of targeting. We show that nucleotide and substrate generate differential gradients of interaction energies that drive the ordered interaction of Get3 with successive effectors. These data also provide more molecular details on how the targeting complex is captured and disassembled by the ER receptor and reveal a previously unidentified role for Get4/5 in recycling Get3 from the ER membrane at the end of the targeting reaction. These results provide general insights into how complex protein interaction cascades are coupled to energy inputs in biological systems.
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23
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The protein targeting factor Get3 functions as ATP-independent chaperone under oxidative stress conditions. Mol Cell 2014; 56:116-27. [PMID: 25242142 DOI: 10.1016/j.molcel.2014.08.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/01/2014] [Accepted: 08/14/2014] [Indexed: 11/23/2022]
Abstract
Exposure of cells to reactive oxygen species (ROS) causes a rapid and significant drop in intracellular ATP levels. This energy depletion negatively affects ATP-dependent chaperone systems, making ROS-mediated protein unfolding and aggregation a potentially very challenging problem. Here we show that Get3, a protein involved in ATP-dependent targeting of tail-anchored (TA) proteins under nonstress conditions, turns into an effective ATP-independent chaperone when oxidized. Activation of Get3's chaperone function, which is a fully reversible process, involves disulfide bond formation, metal release, and its conversion into distinct, higher oligomeric structures. Mutational studies demonstrate that the chaperone activity of Get3 is functionally distinct from and likely mutually exclusive with its targeting function, and responsible for the oxidative stress-sensitive phenotype that has long been noted for yeast cells lacking functional Get3. These results provide convincing evidence that Get3 functions as a redox-regulated chaperone, effectively protecting eukaryotic cells against oxidative protein damage.
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24
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Gristick HB, Rao M, Chartron JW, Rome ME, Shan SO, Clemons WM. Crystal structure of ATP-bound Get3-Get4-Get5 complex reveals regulation of Get3 by Get4. Nat Struct Mol Biol 2014; 21:437-42. [PMID: 24727835 PMCID: PMC4386898 DOI: 10.1038/nsmb.2813] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 03/24/2014] [Indexed: 11/16/2022]
Abstract
Correct localization of membrane proteins is essential to all cells. Chaperone cascades coordinate the capture and handover of substrate proteins from the ribosomes to the target membranes, yet the mechanistic and structural details of these processes remain unclear. Here we investigate the conserved GET pathway, in which the Get4-Get5 complex mediates the handover of tail-anchor (TA) substrates from the cochaperone Sgt2 to the Get3 ATPase, the central targeting factor. We present a crystal structure of a yeast Get3-Get4-Get5 complex in an ATP-bound state and show how Get4 primes Get3 by promoting the optimal configuration for substrate capture. Structure-guided biochemical analyses demonstrate that Get4-mediated regulation of ATP hydrolysis by Get3 is essential to efficient TA-protein targeting. Analogous regulation of other chaperones or targeting factors could provide a general mechanism for ensuring effective substrate capture during protein biogenesis.
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Affiliation(s)
- Harry B. Gristick
- Division of Chemistry and Chemical Engineering, California Institute of Technology, CA, USA
| | - Meera Rao
- Division of Chemistry and Chemical Engineering, California Institute of Technology, CA, USA
| | - Justin W. Chartron
- Division of Chemistry and Chemical Engineering, California Institute of Technology, CA, USA
| | - Michael E. Rome
- Division of Chemistry and Chemical Engineering, California Institute of Technology, CA, USA
| | - Shu-ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, CA, USA
| | - William M. Clemons
- Division of Chemistry and Chemical Engineering, California Institute of Technology, CA, USA
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25
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Formighieri C, Cazzaniga S, Kuras R, Bassi R. Biogenesis of photosynthetic complexes in the chloroplast of Chlamydomonas reinhardtii requires ARSA1, a homolog of prokaryotic arsenite transporter and eukaryotic TRC40 for guided entry of tail-anchored proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:850-61. [PMID: 23167510 DOI: 10.1111/tpj.12077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 11/13/2012] [Accepted: 11/15/2012] [Indexed: 05/08/2023]
Abstract
as1, for antenna size mutant 1, was obtained by insertion mutagenesis of the unicellular green alga Chlamydomonas reinhardtii. This strain has a low chlorophyll content, 8% with respect to the wild type, and displays a general reduction in thylakoid polypeptides. The mutant was found to carry an insertion into a homologous gene, prokaryotic arsenite transporter (ARSA), whose yeast and mammal counterparts were found to be involved in the targeting of tail-anchored (TA) proteins to cytosol-exposed membranes, essential for several cellular functions. Here we present the characterization in a photosynthetic organism of an insertion mutant in an ARSA-homolog gene. The ARSA1 protein was found to be localized in the cytosol, and yet its absence in as1 leads to a small chloroplast and a strongly decreased chlorophyll content per cell. ARSA1 appears to be required for optimal biogenesis of photosynthetic complexes because of its involvement in the accumulation of TOC34, an essential component of the outer chloroplast membrane translocon (TOC) complex, which, in turn, catalyzes the import of nucleus-encoded precursor polypeptides into the chloroplast. Remarkably, the effect of the mutation appears to be restricted to biogenesis of chlorophyll-binding polypeptides and is not compensated by the other ARSA homolog encoded by the C. reinhardtii genome, implying a non-redundant function.
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Affiliation(s)
- Cinzia Formighieri
- Dipartimento di Biotecnologie, Università di Verona, 15, Strada Le Grazie, I-37134 Verona, Italy
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26
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Yamamoto Y, Sakisaka T. Molecular Machinery for Insertion of Tail-Anchored Membrane Proteins into the Endoplasmic Reticulum Membrane in Mammalian Cells. Mol Cell 2012; 48:387-97. [DOI: 10.1016/j.molcel.2012.08.028] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 07/02/2012] [Accepted: 08/27/2012] [Indexed: 11/27/2022]
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27
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Denic V. A portrait of the GET pathway as a surprisingly complicated young man. Trends Biochem Sci 2012; 37:411-7. [PMID: 22951232 DOI: 10.1016/j.tibs.2012.07.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 01/04/2023]
Abstract
Many eukaryotic membrane proteins have a single C-terminal transmembrane domain that anchors them to a variety of organelles in secretory and endocytic pathways. These tail-anchored (TA) proteins are post-translationally inserted into the endoplasmic reticulum by molecular mechanisms that have long remained mysterious. This review describes how, in just the past 5 years, intense research by a handful of laboratories has led to identification of all the key components of one such mechanism, the guided entry of TA proteins (GET) pathway, which is conserved from yeast to man. The GET pathway is both surprisingly complicated and yet more experimentally tractable than most other membrane insertion mechanisms, and is rapidly revealing new fundamental concepts in membrane protein biogenesis.
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Affiliation(s)
- Vladimir Denic
- Department of Molecular and Cellular Biology, Harvard University, Northwest Labs, Cambridge, MA 02138, USA.
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28
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Tail-anchored membrane protein insertion into the endoplasmic reticulum. Nat Rev Mol Cell Biol 2011; 12:787-98. [PMID: 22086371 DOI: 10.1038/nrm3226] [Citation(s) in RCA: 204] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Membrane proteins are inserted into the endoplasmic reticulum (ER) by two highly conserved parallel pathways. The well-studied co-translational pathway uses signal recognition particle (SRP) and its receptor for targeting and the SEC61 translocon for membrane integration. A recently discovered post-translational pathway uses an entirely different set of factors involving transmembrane domain (TMD)-selective cytosolic chaperones and an accompanying receptor at the ER. Elucidation of the structural and mechanistic basis of this post-translational membrane protein insertion pathway highlights general principles shared between the two pathways and key distinctions unique to each.
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29
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Borgese N, Fasana E. Targeting pathways of C-tail-anchored proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:937-46. [DOI: 10.1016/j.bbamem.2010.07.010] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 07/09/2010] [Accepted: 07/10/2010] [Indexed: 10/19/2022]
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30
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Abstract
Cancer can be cured by platinum-based chemotherapy, but resistance is a major cause of treatment failure. Here we present the nematode Caenorhabditis elegans as a model to study interactions between the platinum drug cisplatin and signaling pathways in vivo. Null mutation in a single gene, asna-1, makes worms hypersensitive to cisplatin. The metalloregulated ATPase ASNA-1 promotes insulin secretion and membrane insertion of tail-anchored proteins. Using structural data from ASNA-1 homologues, we identify specific ASNA-1 mutants that are sensitive to cisplatin while still able to promote insulin signaling. Mutational analysis reveals that hypersensitivity of ASNA-1 mutants to cisplatin remains in absence of CEP-1/p53 or apoptosis. Human ASNA1 can substitute for the worm gene, indicating a conserved function. Cisplatin sensitivity is not affected by decreased insulin signaling in wild-type nematodes or restored insulin signaling in asna-1 mutants. These findings provide a functional insight into ASNA-1, demonstrate that C. elegans can be used to characterize cisplatin resistance mechanisms, and suggest that rationally designed drugs against ASNA-1 can sensitize cancer cells to cisplatin.
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Affiliation(s)
- Oskar Hemmingsson
- Division of Surgery, Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden
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31
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Bohnsack MT, Schleiff E. The evolution of protein targeting and translocation systems. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:1115-30. [DOI: 10.1016/j.bbamcr.2010.06.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 05/26/2010] [Accepted: 06/11/2010] [Indexed: 11/28/2022]
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32
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Rabu C, Schmid V, Schwappach B, High S. Biogenesis of tail-anchored proteins: the beginning for the end? J Cell Sci 2010; 122:3605-12. [PMID: 19812306 DOI: 10.1242/jcs.041210] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Tail-anchored proteins are a distinct class of integral membrane proteins located in several eukaryotic organelles, where they perform a diverse range of functions. These proteins have in common the C-terminal location of their transmembrane anchor and the resulting post-translational nature of their membrane insertion, which, unlike the co-translational membrane insertion of most other proteins, is not coupled to ongoing protein synthesis. The study of tail-anchored proteins has provided a paradigm for understanding the components and pathways that mediate post-translational biogenesis of membrane proteins at the endoplasmic reticulum. In this Commentary, we review recent studies that have converged at a consensus regarding the molecular mechanisms that underlie this process--namely, that multiple pathways underlie the biogenesis of tail-anchored proteins at the endoplasmic reticulum.
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Affiliation(s)
- Catherine Rabu
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
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33
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Hu J, Li J, Qian X, Denic V, Sha B. The crystal structures of yeast Get3 suggest a mechanism for tail-anchored protein membrane insertion. PLoS One 2009; 4:e8061. [PMID: 19956640 PMCID: PMC2778870 DOI: 10.1371/journal.pone.0008061] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 10/30/2009] [Indexed: 12/31/2022] Open
Abstract
Tail-anchored (TA) proteins represent a unique class of membrane proteins that contain a single C-terminal transmembrane helix. The post-translational insertion of the yeast TA proteins into the ER membrane requires the Golgi ER trafficking (GET) complex which contains Get1, Get2 and Get3. Get3 is an ATPase that recognizes and binds the C-terminal transmembrane domain (TMD) of the TA proteins. We have determined the crystal structures of Get3 from two yeast species, S. cerevisiae and D. hansenii, respectively. These high resolution crystal structures show that Get3 contains a nucleotide-binding domain and a "finger" domain for binding the TA protein TMD. A large hydrophobic groove on the finger domain of S. cerevisiae Get3 structure might represent the binding site for TMD of TA proteins. A hydrophobic helix from a symmetry-related Get3 molecule sits in the TMD-binding groove and mimics the TA binding scenario. Interestingly, the crystal structures of the Get3 dimers from S. cerevisiae and D. hansenii exhibit distinct conformations. The S. cerevisiae Get3 dimer structure does not contain nucleotides and maintains an "open" conformation, while the D. hansenii Get3 dimer structure binds ADP and stays in a "closed" conformation. We propose that the conformational changes to switch the Get3 between the open and closed conformations may facilitate the membrane insertions for TA proteins.
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Affiliation(s)
- Junbin Hu
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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34
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Structural insights into tail-anchored protein binding and membrane insertion by Get3. Proc Natl Acad Sci U S A 2009; 106:21131-6. [PMID: 19948960 DOI: 10.1073/pnas.0910223106] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Tail-anchored (TA) membrane proteins are involved in a variety of important cellular functions, including membrane fusion, protein translocation, and apoptosis. The ATPase Get3 (Asna1, TRC40) was identified recently as the endoplasmic reticulum targeting factor of TA proteins. Get3 consists of an ATPase and alpha-helical subdomain enriched in methionine and glycine residues. We present structural and biochemical analyses of Get3 alone as well as in complex with a TA protein, ribosome-associated membrane protein 4 (Ramp4). The ATPase domains form an extensive dimer interface that encloses 2 nucleotides in a head-to-head orientation and a zinc ion. Amide proton exchange mass spectrometry shows that the alpha-helical subdomain of Get3 displays considerable flexibility in solution and maps the TA protein-binding site to the alpha-helical subdomain. The non-hydrolyzable ATP analogue AMPPNP-Mg(2+)- and ADP-Mg(2+)-bound crystal structures representing the pre- and posthydrolysis states are both in a closed form. In the absence of a TA protein cargo, ATP hydrolysis does not seem to be possible. Comparison with the ADP.AlF(4)(-)-bound structure representing the transition state (Mateja A, et al. (2009) Nature 461:361-366) indicates how the presence of a TA protein is communicated to the ATP-binding site. In vitro membrane insertion studies show that recombinant Get3 inserts Ramp4 in a nucleotide- and receptor-dependent manner. Although ATP hydrolysis is not required for Ramp4 insertion per se, it seems to be required for efficient insertion. We postulate that ATP hydrolysis is needed to release Get3 from its receptor. Taken together, our results provide mechanistic insights into posttranslational targeting of TA membrane proteins by Get3.
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35
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Schuldiner M, Metz J, Schmid V, Denic V, Rakwalska M, Schmitt HD, Schwappach B, Weissman JS. The GET complex mediates insertion of tail-anchored proteins into the ER membrane. Cell 2008; 134:634-45. [PMID: 18724936 PMCID: PMC2572727 DOI: 10.1016/j.cell.2008.06.025] [Citation(s) in RCA: 387] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 05/02/2008] [Accepted: 06/13/2008] [Indexed: 11/20/2022]
Abstract
Tail-anchored (TA) proteins, defined by the presence of a single C-terminal transmembrane domain (TMD), play critical roles throughout the secretory pathway and in mitochondria, yet the machinery responsible for their proper membrane insertion remains poorly characterized. Here we show that Get3, the yeast homolog of the TA-interacting factor Asna1/Trc40, specifically recognizes TMDs of TA proteins destined for the secretory pathway. Get3 recognition represents a key decision step, whose loss can lead to misinsertion of TA proteins into mitochondria. Get3-TA protein complexes are recruited for endoplasmic reticulum (ER) membrane insertion by the Get1/Get2 receptor. In vivo, the absence of Get1/Get2 leads to cytosolic aggregation of Get3-TA complexes and broad defects in TA protein biogenesis. In vitro reconstitution demonstrates that the Get proteins directly mediate insertion of newly synthesized TA proteins into ER membranes. Thus, the GET complex represents a critical mechanism for ensuring efficient and accurate targeting of TA proteins.
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Affiliation(s)
- Maya Schuldiner
- Howard Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, and California Institute for Quantitative Biosciences, San Francisco, CA 94158, USA
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36
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Rabu C, Wipf P, Brodsky JL, High S. A precursor-specific role for Hsp40/Hsc70 during tail-anchored protein integration at the endoplasmic reticulum. J Biol Chem 2008; 283:27504-27513. [PMID: 18667436 DOI: 10.1074/jbc.m804591200] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tail-anchored (TA) protein synthesis at the endoplasmic reticulum (ER) represents a distinct and novel process that provides a paradigm for understanding post-translational membrane insertion in eukaryotes. The major route for delivering TA proteins to the ER requires both ATP and one or more cytosolic factors that facilitate efficient membrane insertion. Until recently, the identity of these cytosolic components was elusive, but two candidates have now been suggested to promote ATP-dependent TA protein integration. The first is the cytosolic chaperone complex of Hsp40/Hsc70, and the second is a novel ATPase denoted Asna-1 or TRC40. In this study we focus on the role of the Hsp40/Hsc70 complex in promoting TA protein biogenesis at the ER. We show that the membrane integration of most TA proteins is stimulated by Hsp40/Hsc70 when using purified components and a reconstituted system. In contrast, when both Hsp40/Hsc70 and Asna-1/TRC40 are provided as a complete system, small molecule inhibition of Hsp40/Hsc70 indicates that only a subset of TA proteins are obligatory clients for this chaperone-mediated delivery route. We show that the hydrophobicity of the TA region dictates whether a precursor is delivered to the ER via the Hsp40/Hsc70 or Asna-1/TRC40-dependent route, and we conclude that these distinct cytosolic ATPases are responsible for two different ATP-dependent pathways of TA protein biogenesis.
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Affiliation(s)
- Catherine Rabu
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Stephen High
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, United Kingdom.
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37
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Abstract
Many membrane proteins are inserted into cellular membranes via a carboxy-terminal tail-anchor segment, but the mechanism of insertion is poorly understood. In this issue of Cell, Stefanovic and Hegde (2007) report the identification and initial characterization of a soluble ATP-dependent receptor for the insertion of newly synthesized tail-anchored membrane proteins.
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Affiliation(s)
- Elisabet C Mandon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605-2324, USA
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38
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Abstract
Because arsenic is the most prevalent environmental toxin, it is imperative that we understand the mechanisms of metalloid detoxification. In prokaryotes, arsenic detoxification is accomplished by chromosomal and plasmid-borne operon-encoded efflux systems. Bacterial ArsA ATPase is the catalytic component of an oxyanion pump that is responsible for resistance to arsenite (As(III)) and antimonite (Sb(III)). Here, we describe the identification of a Caenorhabditis elegans homolog (asna-1) that encodes the ATPase component of the Escherichia coli As(III) and Sb(III) transporter. We evaluated the responses of wild-type and asna-1-mutant nematodes to various metal ions and found that asna-1-mutant nematodes are more sensitive to As(III) and Sb(III) toxicity than are wild-type animals. These results provide evidence that ASNA-1 is required for C. elegans' defense against As(III) and Sb(III) toxicity. A purified maltose-binding protein (MBP)-ASNA-1 fusion protein was biochemically characterized, and its properties compared with those of ArsAs. The ATPase activity of the ASNA-1 protein was dependent on the presence of As(III) or Sb(III). As(III) stimulated ATPase activity by 2 +/- 0.2-fold, whereas Sb(III) stimulated it by 4.6 +/- 0.15-fold. The results indicate that As(III)- and Sb(III)-stimulated ArsA ATPase activities are not restricted to bacteria, but extend to animals, by demonstrating that the asna-1 gene from the nematode, C. elegans, encodes a functional ArsA ATPase whose activity is stimulated by As(III) and Sb(III) and which is critical for As(III) and Sb(III) tolerance in the intact organism.
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Affiliation(s)
- Yuen-Yi Tseng
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
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39
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Kao G, Nordenson C, Still M, Rönnlund A, Tuck S, Naredi P. ASNA-1 positively regulates insulin secretion in C. elegans and mammalian cells. Cell 2007; 128:577-87. [PMID: 17289575 DOI: 10.1016/j.cell.2006.12.031] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 11/03/2006] [Accepted: 12/12/2006] [Indexed: 11/17/2022]
Abstract
C. elegans worms hatching in the absence of food show growth arrest during the first larval stage (L1). While much has been learned about the later diapause, dauer, which worms enter under adverse conditions, much less is known about the mechanisms governing L1 arrest. Here we show that worms lacking activity of the asna-1 gene arrest growth reversibly at the L1 stage even when food is abundant. asna-1 encodes an ATPase that functions nonautonomously to regulate growth. asna-1 is expressed in a restricted set of sensory neurons and in insulin-producing intestinal cells. asna-1 mutants are reduced in insulin secretion while overexpression of asna-1 mimics the effects of insulin overexpression. Human ASNA1 is highly expressed in pancreatic beta cells, but not in other pancreatic endocrine cell types, and regulates insulin secretion in cultured cells. We propose that ASNA1 is an evolutionarily conserved modulator of insulin signaling.
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Affiliation(s)
- Gautam Kao
- Umeå Center for Molecular Pathogenesis, Umeå University, SE-901 87 Umeå, Sweden
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Stefanovic S, Hegde RS. Identification of a Targeting Factor for Posttranslational Membrane Protein Insertion into the ER. Cell 2007; 128:1147-59. [PMID: 17382883 DOI: 10.1016/j.cell.2007.01.036] [Citation(s) in RCA: 315] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 12/08/2006] [Accepted: 01/05/2007] [Indexed: 11/28/2022]
Abstract
Hundreds of proteins are anchored in intracellular membranes by a single transmembrane domain (TMD) close to the C terminus. Although these tail-anchored (TA) proteins serve numerous essential roles in cells, components of their targeting and insertion pathways have long remained elusive. Here we reveal a cytosolic TMD recognition complex (TRC) that targets TA proteins for insertion into the ER membrane. The highly conserved, 40 kDa ATPase subunit of TRC (which we termed TRC40) was identified as Asna-1. TRC40/Asna-1 interacts posttranslationally with TA proteins in a TMD-dependent manner for delivery to a proteinaceous receptor at the ER membrane. Subsequent release from TRC40/Asna-1 and insertion into the membrane depends on ATP hydrolysis. Consequently, an ATPase-deficient mutant of TRC40/Asna-1 dominantly inhibited TA protein insertion selectively without influencing other translocation pathways. Thus, TRC40/Asna-1 represents an integral component of a posttranslational pathway of membrane protein insertion whose targeting is mediated by TRC.
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Affiliation(s)
- Sandra Stefanovic
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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