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Pohlschroder M, Pfeiffer F, Schulze S, Abdul Halim MF. Archaeal cell surface biogenesis. FEMS Microbiol Rev 2018; 42:694-717. [PMID: 29912330 PMCID: PMC6098224 DOI: 10.1093/femsre/fuy027] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/12/2018] [Indexed: 12/13/2022] Open
Abstract
Cell surfaces are critical for diverse functions across all domains of life, from cell-cell communication and nutrient uptake to cell stability and surface attachment. While certain aspects of the mechanisms supporting the biosynthesis of the archaeal cell surface are unique, likely due to important differences in cell surface compositions between domains, others are shared with bacteria or eukaryotes or both. Based on recent studies completed on a phylogenetically diverse array of archaea, from a wide variety of habitats, here we discuss advances in the characterization of mechanisms underpinning archaeal cell surface biogenesis. These include those facilitating co- and post-translational protein targeting to the cell surface, transport into and across the archaeal lipid membrane, and protein anchoring strategies. We also discuss, in some detail, the assembly of specific cell surface structures, such as the archaeal S-layer and the type IV pili. We will highlight the importance of post-translational protein modifications, such as lipid attachment and glycosylation, in the biosynthesis as well as the regulation of the functions of these cell surface structures and present the differences and similarities in the biogenesis of type IV pili across prokaryotic domains.
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Affiliation(s)
| | - Friedhelm Pfeiffer
- Computational Biology Group, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Stefan Schulze
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Abstract
The insertion and assembly of proteins into the inner membrane of bacteria are crucial for many cellular processes, including cellular respiration, signal transduction, and ion and pH homeostasis. This process requires efficient membrane targeting and insertion of proteins into the lipid bilayer in their correct orientation and proper conformation. Playing center stage in these events are the targeting components, signal recognition particle (SRP) and the SRP receptor FtsY, as well as the insertion components, the Sec translocon and the YidC insertase. Here, we will discuss new insights provided from the recent high-resolution structures of these proteins. In addition, we will review the mechanism by which a variety of proteins with different topologies are inserted into the inner membrane of Gram-negative bacteria. Finally, we report on the energetics of this process and provide information on how membrane insertion occurs in Gram-positive bacteria and Archaea. It should be noted that most of what we know about membrane protein assembly in bacteria is based on studies conducted in Escherichia coli.
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Affiliation(s)
- Andreas Kuhn
- Institute for Microbiology and Molecular Biology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, 79104, Freiburg, Germany
| | - Ross E Dalbey
- Department of Chemistry, The Ohio State University, Columbus, OH 43210
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3
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Gupta S, Roy M, Ghosh A. The Archaeal Signal Recognition Particle: Present Understanding and Future Perspective. Curr Microbiol 2016; 74:284-297. [DOI: 10.1007/s00284-016-1167-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
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Draycheva A, Bornemann T, Ryazanov S, Lakomek N, Wintermeyer W. The bacterial SRP receptor, FtsY, is activated on binding to the translocon. Mol Microbiol 2016; 102:152-67. [DOI: 10.1111/mmi.13452] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2016] [Indexed: 01/10/2023]
Affiliation(s)
- Albena Draycheva
- Department of Physical BiochemistryMax Planck Institute for Biophysical ChemistryGöttingen Germany
| | - Thomas Bornemann
- Department of Physical BiochemistryMax Planck Institute for Biophysical ChemistryGöttingen Germany
| | - Sergey Ryazanov
- Department of NMR‐based Structural BiologyMax Planck Institute for Biophysical ChemistryGöttingen Germany
| | - Nils‐Alexander Lakomek
- Department of NMR‐based Structural BiologyMax Planck Institute for Biophysical ChemistryGöttingen Germany
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, Solid‐state NMRETH ZürichZürich Switzerland
| | - Wolfgang Wintermeyer
- Department of Physical BiochemistryMax Planck Institute for Biophysical ChemistryGöttingen Germany
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Kuhn P, Weiche B, Sturm L, Sommer E, Drepper F, Warscheid B, Sourjik V, Koch HG. The bacterial SRP receptor, SecA and the ribosome use overlapping binding sites on the SecY translocon. Traffic 2011; 12:563-78. [PMID: 21255212 DOI: 10.1111/j.1600-0854.2011.01167.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Signal recognition particle (SRP)-dependent protein targeting is a universally conserved process that delivers proteins to the bacterial cytoplasmic membrane or to the endoplasmic reticulum membrane in eukaryotes. Crucial during targeting is the transfer of the ribosome-nascent chain complex (RNC) from SRP to the Sec translocon. In eukaryotes, this step is co-ordinated by the SRβ subunit of the SRP receptor (SR), which probably senses a vacant translocon by direct interaction with the translocon. Bacteria lack the SRβ subunit and how they co-ordinate RNC transfer is unknown. By site-directed cross-linking and fluorescence resonance energy transfer (FRET) analyses, we show that FtsY, the bacterial SRα homologue, binds to the exposed C4/C5 loops of SecY, the central component of the bacterial Sec translocon. The same loops serve also as binding sites for SecA and the ribosome. The FtsY-SecY interaction involves at least the A domain of FtsY, which attributes an important function to this so far ill-defined domain. Binding of FtsY to SecY residues, which are also used by SecA and the ribosome, probably allows FtsY to sense an available translocon and to align the incoming SRP-RNC with the protein conducting channel. Thus, the Escherichia coli FtsY encompasses the functions of both the eukaryotic SRα and SRβ subunits in one single protein.
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Affiliation(s)
- Patrick Kuhn
- Institut für Biochemie und Molekularbiologie, ZBMZ, Stefan-Meier-Str. 17, D-79104 Freiburg, Germany
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Shaping the archaeal cell envelope. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2010; 2010:608243. [PMID: 20671907 PMCID: PMC2910488 DOI: 10.1155/2010/608243] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 05/29/2010] [Indexed: 12/12/2022]
Abstract
Although archaea have a similar cellular organization as other prokaryotes, the lipid composition of their membranes and their cell surface is unique. Here we discuss recent developments in our understanding of the archaeal protein secretion mechanisms, the assembly of macromolecular cell surface structures, and the release of S-layer-coated vesicles from the archaeal membrane.
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Archaea signal recognition particle shows the way. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2010; 2010:485051. [PMID: 20672053 PMCID: PMC2905702 DOI: 10.1155/2010/485051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 05/14/2010] [Indexed: 01/24/2023]
Abstract
Archaea SRP is composed of an SRP RNA molecule and two bound proteins named SRP19 and SRP54. Regulated by the binding and hydrolysis of guanosine triphosphates, the RNA-bound SRP54 protein transiently associates not only with the hydrophobic signal sequence as it emerges from the ribosomal exit tunnel, but also interacts with the membrane-associated SRP receptor (FtsY). Comparative analyses of the archaea genomes and their SRP component sequences, combined with structural and biochemical data, support a prominent role of the SRP RNA in the assembly and function of the archaea SRP. The 5e motif, which in eukaryotes binds a 72 kilodalton protein, is preserved in most archaea SRP RNAs despite the lack of an archaea SRP72 homolog. The primary function of the 5e region may be to serve as a hinge, strategically positioned between the small and large SRP domain, allowing the elongated SRP to bind simultaneously to distant ribosomal sites. SRP19, required in eukaryotes for initiating SRP assembly, appears to play a subordinate role in the archaea SRP or may be defunct. The N-terminal A region and a novel C-terminal R region of the archaea SRP receptor (FtsY) are strikingly diverse or absent even among the members of a taxonomic subgroup.
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Calo D, Eichler J. Crossing the membrane in Archaea, the third domain of life. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:885-91. [PMID: 20347718 DOI: 10.1016/j.bbamem.2010.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 03/18/2010] [Accepted: 03/18/2010] [Indexed: 11/16/2022]
Abstract
Many of the recent advancements in the field of protein translocation, particularly from the structural perspective, have relied on Archaea. For instance, the solved structures of the translocon from the methanoarchaeon Methanocaldococcus jannaschii of the ribosomal large subunit from the haloarchaeon Haloarcula marismortui and of components of the SRP pathway from several archaeal species have provided novel insight into various aspects of the translocation event. Given the major contribution that Archaea have made to our understanding of how proteins enter and traverse membranes, it is surprising that relatively little is known of protein translocation in Archaea in comparison to the well-defined translocation pathways of Eukarya and Bacteria. What is known, however, points to archaeal translocation as comprising a mosaic of eukaryal and bacterial traits together with aspects of the process seemingly unique to this, the third domain of life. Here, current understanding of archaeal protein translocation is considered. This article is part of a Special Issue entitled Protein translocation across or insertion into membranes.
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Affiliation(s)
- Doron Calo
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva 84105, Israel
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Maeda I, Hirata A, Shoji M, Ueda S, Yoshida K. Functional substitution of the transient membrane-anchor domain inEscherichia coliFtsY with an N-terminal hydrophobic segment ofStreptomyces lividansFtsY. FEMS Microbiol Lett 2008; 287:85-90. [DOI: 10.1111/j.1574-6968.2008.01297.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Genomics and functional genomics with haloarchaea. Arch Microbiol 2008; 190:197-215. [PMID: 18493745 DOI: 10.1007/s00203-008-0376-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 04/08/2008] [Accepted: 04/20/2008] [Indexed: 10/22/2022]
Abstract
The first haloarchaeal genome was published in 2000 and today five genome sequences are available. Transcriptome and proteome analyses have been established for two and three haloarchaeal species, respectively, and more than 20 studies using these functional genomic approaches have been published in the last two years. These studies gave global overviews of metabolic regulation (aerobic and anaerobic respiration, phototrophy, carbon source usage), stress response (UV, X-rays, transition metals, osmotic and temperature stress), cell cycle-dependent transcript level regulation, and transcript half-lives. The only translatome analysis available for any prokaryotic species revealed that 10 and 20% of all transcripts are translationally regulated in Haloferax volcanii and Halobacterium salinarum, respectively. Very effective methods for the construction of in frame deletion mutants have been established recently for haloarchaea and are intensively used to unravel the biological roles of genes in this group. Bioinformatic analyses include both cross-genome comparisons as well as integration of genomic data with experimental results. The first systems biology approaches have been performed that used experimental data to construct predictive models of gene expression and metabolism, respectively. In this contribution the current status of genomics, functional genomics, and molecular genetics of haloarchaea is summarized and selected examples are discussed.
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Identification of AglE, a second glycosyltransferase involved in N glycosylation of the Haloferax volcanii S-layer glycoprotein. J Bacteriol 2008; 190:3140-6. [PMID: 18310347 PMCID: PMC2347396 DOI: 10.1128/jb.00056-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Archaea, like Eukarya and Bacteria, are able to N glycosylate select protein targets. However, in contrast to relatively advanced understanding of the eukaryal N glycosylation process and the information being amassed on the bacterial process, little is known of this posttranslational modification in Archaea. Toward remedying this situation, the present report continues ongoing efforts to identify components involved in the N glycosylation of the Haloferax volcanii S-layer glycoprotein. By combining gene deletion together with mass spectrometry, AglE, originally identified as a homologue of murine Dpm1, was shown to play a role in the addition of the 190-Da sugar subunit of the novel pentasaccharide decorating the S-layer glycoprotein. Topological analysis of an AglE-based chimeric reporter assigns AglE as an integral membrane protein, with its N terminus and putative active site facing the cytoplasm. These finding, therefore, contribute to the developing picture of the N glycosylation pathway in Archaea.
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12
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Weiche B, Bürk J, Angelini S, Schiltz E, Thumfart JO, Koch HG. A cleavable N-terminal membrane anchor is involved in membrane binding of the Escherichia coli SRP receptor. J Mol Biol 2008; 377:761-73. [PMID: 18281057 DOI: 10.1016/j.jmb.2008.01.040] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 12/27/2007] [Accepted: 01/15/2008] [Indexed: 10/22/2022]
Abstract
Different from eukaryotes, the bacterial signal recognition particle (SRP) receptor lacks a membrane-tethering SRP receptor (SR) beta subunit and is composed of only the SR alpha homologue FtsY. FtsY is a modular protein composed of three domains. The N- and G-domains of FtsY are highly similar to the corresponding domains of Ffh/SRP54 and SR alpha and constitute the essential core of FtsY. In contrast, the weakly conserved N-terminal A-domain does not seem to be essential, and its exact function is unknown. Our data show that a 14-amino-acid-long positively charged region at the N-terminus of the A-domain is involved in stabilizing the FtsY-SecYEG interaction. Mutant analyses reveal that the positively charged residues are crucial for this function, and we propose that the 14-amino-acid region serves as a transient lipid anchor. In its absence, the activity of FtsY to support cotranslational integration is reduced to about 50%. Strikingly, in vivo, a truncated isoform of FtsY that lacks exactly these first 14 amino acids exists. Different from full-length FtsY, which primarily cofractionates with the membrane, the N-terminally truncated isoform is primarily present in the soluble fraction. Mutating the conserved glycine residue at position 14 prevents the formation of the truncated isoform and impairs the activity of FtsY in cotranslational targeting. These data suggest that membrane binding and function of FtsY are in part regulated by proteolytic cleavage of the conserved 14-amino-acid motif.
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Affiliation(s)
- Benjamin Weiche
- Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
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Gawronski-Salerno J, Coon JS, Focia PJ, Freymann DM. X-ray structure of the T. aquaticus FtsY:GDP complex suggests functional roles for the C-terminal helix of the SRP GTPases. Proteins 2007; 66:984-95. [PMID: 17186523 PMCID: PMC3543818 DOI: 10.1002/prot.21200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
FtsY and Ffh are structurally similar prokaryotic Signal Recognition Particle GTPases that play an essential role in the Signal Recognition Particle (SRP)-mediated cotranslational targeting of proteins to the membrane. The two GTPases assemble in a GTP-dependent manner to form a heterodimeric SRP targeting complex. We report here the 2.1 A X-ray structure of FtsY from T. aquaticus bound to GDP. The structure of the monomeric protein reveals, unexpectedly, canonical binding interactions for GDP. A comparison of the structures of the monomeric and complexed FtsY NG GTPase domain suggests that it undergoes a conformational change similar to that of Ffh NG during the assembly of the symmetric heterodimeric complex. However, in contrast to Ffh, in which the C-terminal helix shifts independently of the other subdomains, the C-terminal helix and N domain of T. aquaticus FtsY together behave as a rigid body during assembly, suggesting distinct mechanisms by which the interactions of the NG domain "module" are regulated in the context of the two SRP GTPases.
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Affiliation(s)
| | | | | | - Douglas M. Freymann
- Correspondence to: Douglas M. Freymann, Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, IL 60611.
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Kiefer D, Kuhn A. YidC as an essential and multifunctional component in membrane protein assembly. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 259:113-38. [PMID: 17425940 DOI: 10.1016/s0074-7696(06)59003-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Membrane proteins fulfill a number of vital functions in prokaryotic and eukaryotic cells. They are often organized in multicomponent complexes, folded within the membrane bilayer and interacting with the cytoplasmic and periplasmic or external soluble compartments. For the biogenesis of integral membrane proteins, the essential biochemical steps are (1) the insertion and topogenesis of the transmembrane protein segments into the lipid bilayer, (2) the three-dimensional folding of the translocated hydrophilic domains, and (3) the assembly into multimeric complexes. Intensive research has elucidated the basic mechanisms of membrane protein insertion in the homologous translocation machineries of different cellular systems. Whereas the Sec translocation system is found in the endoplasmic reticulum of eukaryotic cells and in the prokaryotic plasma membrane, the YidC-Oxa1 membrane insertase is present in prokaryotic and organellar membranes. This review focuses on the discoveries of the YidC system in bacterial as well as the Oxa1/Alb3 protein family of eukaryotic cells and will particularly emphasize evolutionary aspects.
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Affiliation(s)
- Dorothee Kiefer
- Department of Microbiology, University of Hohenheim, D-70599 Stuttgart, Germany
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Hand NJ, Klein R, Laskewitz A, Pohlschröder M. Archaeal and bacterial SecD and SecF homologs exhibit striking structural and functional conservation. J Bacteriol 2006; 188:1251-9. [PMID: 16452406 PMCID: PMC1367261 DOI: 10.1128/jb.188.4.1251-1259.2006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The majority of secretory proteins are translocated into and across hydrophobic membranes via the universally conserved Sec pore. Accessory proteins, including the SecDF-YajC Escherichia coli membrane complex, are required for efficient protein secretion. E. coli SecDF-YajC has been proposed to be involved in the membrane cycling of SecA, the cytoplasmic bacterial translocation ATPase, and in the stabilizing of SecG, a subunit of the Sec pore. While there are no identified archaeal homologs of either SecA or SecG, many archaea possess homologs of SecD and SecF. Here, we present the first study that addresses the function of archaeal SecD and SecF homologs. We show that the SecD and SecF components in the model archaeon Haloferax volcanii form a cytoplasmic membrane complex in the native host. Furthermore, as in E. coli, an H. volcanii deltasecFD mutant strain exhibits both severe cold sensitivity and a Sec-specific protein translocation defect. Taken together, these results demonstrate significant functional conservation among the prokaryotic SecD and SecF homologs despite the distinct composition of their translocation machineries.
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Affiliation(s)
- Nicholas J Hand
- Department of Biology, University of Pennsylvania, 201 Leidy Laboratories, 415 South University Ave., Philadelphia, Pennsylvania 19104, USA
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Pohlschröder M, Giménez MI, Jarrell KF. Protein transport in Archaea: Sec and twin arginine translocation pathways. Curr Opin Microbiol 2005; 8:713-9. [PMID: 16257258 DOI: 10.1016/j.mib.2005.10.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 10/11/2005] [Indexed: 12/01/2022]
Abstract
The transport of proteins into and across hydrophobic membranes is an essential cellular process. The majority of proteins that are translocated in an unfolded conformation traverse the membrane by way of the universally conserved Sec pathway, whereas the twin arginine translocation pathway is responsible for the transport of folded proteins across the membrane. Structural, biochemical and genetic analyses of these processes in Archaea have revealed unique archaeal features, and have also provided a better understanding of these pathways in organisms of all domains. Further study of these pathways in Archaea might elucidate fundamental principles involved in each type of transport and could help determine their relative costs and benefits as well as evolutionary adaptations in protein secretion strategies.
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Pohlschröder M, Hartmann E, Hand NJ, Dilks K, Haddad A. DIVERSITY AND EVOLUTION OF PROTEIN TRANSLOCATION. Annu Rev Microbiol 2005; 59:91-111. [PMID: 16153164 DOI: 10.1146/annurev.micro.59.030804.121353] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells need to translocate proteins into and across hydrophobic membranes in order to interact with the extracellular environment. Although a subset of proteins are thought to spontaneously insert into lipid bilayers, translocation of most transported proteins requires additional cellular components. Such components catalyze efficient lateral transport into or across cellular membranes in prokaryotes and eukaryotes. These include, among others, the conserved YidC/Oxa1/Alb3 proteins as well as components of the Sec and the Tat pathways. Our current knowledge of the function and distribution of these components and their corresponding pathways in organisms of the three domains of life is reviewed. On the basis of this information, the evolution of protein translocation is discussed.
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Affiliation(s)
- Mechthild Pohlschröder
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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