|Gene:||tatC||Accession Numbers: EG11479 (EcoCyc), b3839, ECK3832|
Synonyms: mttB, yigU, yigV
Component of: TatABCE protein export complex (extended summary available)
TatC is a subunit of the TatABCE (twin-arginine translocation) complex for the export of folded proteins across the cytoplasmic membrane. Although its exact function is not known, it has been shown through deletion mutation studies [Bogsch98] to be essential for Tat-dependent protein export. Membrane topology predictions using experimentally determined C terminus locations indicate that TatC has 6 transmembrane helices and the C-terminus is located in the periplasm [Rapp04],[Drew02]. TatC may form functional dimers [Maldonado11].
tatC is one of a network of genes believed to play a role in promoting the stress-induced mutagenesis (SIM) response of E. coli K-12 [Al12].
Locations: inner membrane
|Map Position: [4,020,759 -> 4,021,535] (86.66 centisomes, 312°)||Length: 777 bp / 258 aa|
Molecular Weight of Polypeptide: 28.876 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0012547 , DIP:DIP-58537N , EchoBASE:EB1445 , EcoGene:EG11479 , EcoliWiki:b3839 , Mint:MINT-8083961 , OU-Microarray:b3839 , PortEco:tatC , PR:PRO_000024030 , Protein Model Portal:P69423 , RefSeq:NP_418282 , RegulonDB:EG11479 , SMR:P69423 , String:511145.b3839 , UniProt:P69423
|Biological Process:||GO:0065002 - intracellular protein transmembrane transport
GO:0006810 - transport [UniProtGOA11a]
GO:0015031 - protein transport [UniProtGOA11a]
GO:0043953 - protein transport by the Tat complex [GOA06]
|Molecular Function:||GO:0005515 - protein binding
GO:0008565 - protein transporter activity [Bogsch98]
GO:0009977 - proton motive force dependent protein transmembrane transporter activity [Yahr01]
GO:0008320 - protein transmembrane transporter activity [GOA06]
|Cellular Component:||GO:0005622 - intracellular
GO:0005886 - plasma membrane [UniProtGOA11, UniProtGOA11a, DiazMejia09, Zhang07, Daley05]
GO:0016020 - membrane [UniProtGOA11a, Wexler00]
GO:0033281 - TAT protein transport complex [GOA06, Bolhuis01]
GO:0005887 - integral component of plasma membrane [GOA06]
GO:0016021 - integral component of membrane [UniProtGOA11a, GOA01a]
|MultiFun Terms:||cell structure → membrane|
|transport → Electrochemical potential driven transporters → Porters (Uni-, Sym- and Antiporters)|
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB enriched||Yes||37||Aerobic||6.95||Yes [Gerdes03, Comment 1]|
|LB Lennox||Yes||37||Aerobic||7||Yes [Baba06, Comment 2]|
|M9 medium with 1% glycerol||Yes||37||Aerobic||7.2||0.35||Yes [Joyce06, Comment 3]|
|MOPS medium with 0.4% glucose||Yes||37||Aerobic||7.2||0.22||Yes [Baba06, Comment 2]|
Subunit of: TatABCE protein export complex
Subunit composition of TatABCE protein export complex = [TatB][TatC][TatE][TatA]
The twin-arginine translocation (Tat) system works in parallel with the E. coli Sec translocation system to transport folded proteins across the cytoplasmic membrane [Weiner98]. While the Sec system transports unfolded proteins, Tat translocase functions to move structured macromolecular substrates, usually containing cofactors, across the cytoplasmic membrane. These proteins include those critical for bacterial respiratory and photosynthetic energy metabolism. Substrates utilizing the Tat pathway are characterized by essentially invariant amino-terminal sequences which contain consecutive arginine residues.
Cofactor-containing Tat substrates acquire their cofactors in the cytoplasm where they attain a folded conformation [Berks00]. In studies using mutated tat strains [Sargent98], precursor proteins that accumulate in the cytoplasm contain cofactors. In even more direct studies using folded green fluorescent protein (GFP) fused with the Tat signal peptide [Santini01], the GFP was found to localize to the periplasm.
The Tat apparatus in E. coli is encoded by genes located in two genetic loci. The tatA operon encodes tatABCD; tatE is coded for in a separate locus [Bogsch98]. TatA, TatB and TatE are similar in structure, predicted to comprise a membrane-spanning alpha helix at the amino terminus, followed by an amphipathic helix at the cytoplasmic side of the membrane and a variable-length carboxy terminus. TatA has been shown to be a fully integral membrane protein [De01a]. TatA and TatE share 50% sequence identity and share overlapping functions in Tat translocation. Deletion of either of these genes results in a decrease in the range of substrates, while deletions in both results in complete loss of Tat-dependent export [Sargent98]. Although TatB has 20% sequence identity with TatA/TatE, it serves a distinct function in export. A deletion mutation of tatB alone is enough to completely abolish the translocation of some but not all endogenous Tat substrates [Ize02]. TatC has similarly been shown to be essential for Tat-dependent protein export [Bogsch98]. tatD encodes a soluble cytoplasmic protein with nuclease activity [Wexler00]. Deletion studies of tatD and two of its homologues indicate that TatD family proteins are not essential for Tat-dependent protein translocation.
Functionally, protein translocation in the Tat system is energized exclusively by a transmembrane proton electrochemical gradient with no involvement of nucleotide hydrolysis [Mould91] unlike the Sec translocation system which is powered by ATP hydrolysis.
Localization studies using fusion proteins with green fluorescent protein (GFP) demonstrated that TatA, TatB and TatC proteins all localize to the cellular poles, suggesting that active translocon poles are primarily located at polar positions in E. coli [Berthelmann04].
Within the purified Tat complex, TatB and TatC are present in a strict 1:1 ration and a TatBC fusion protein supports Tat dependent transport [Bolhuis01]. Three-dimensional structures of TatBC-substrate complexes and unliganded TatBC have been obtained by single particle electron microscopy. The structures show substrate binding on the periphery of the TatBC complex and suggest that TatBC undergoes structural reorganisation upon substrate binding [Tarry09].
An experimental approach using alkaline phosphatase (PhoA) fusions to protein signal sequences has allowed discrimination between the major modes of transport, including the Tat protein export system, across the inner membrane [Marrichi08].
Locations: inner membrane
|Biological Process:||GO:0065002 - intracellular protein transmembrane transport [Weiner98, Bolhuis01]|
|Molecular Function:||GO:0009977 - proton motive force dependent protein transmembrane transporter activity [Yahr01]|
|Cellular Component:||GO:0033281 - TAT protein transport complex [Bolhuis01]|
Enzymatic reaction of: TatABCE protein export complex
|Chain||2 -> 258|
|Transmembrane-Region||24 -> 44|
|Transmembrane-Region||76 -> 96|
|Transmembrane-Region||116 -> 136|
|Transmembrane-Region||157 -> 177|
|Transmembrane-Region||193 -> 210|
|Transmembrane-Region||212 -> 232|
10/20/97 Gene b3839 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11479; confirmed by SwissProt match.
Al12: Al Mamun AA, Lombardo MJ, Shee C, Lisewski AM, Gonzalez C, Lin D, Nehring RB, Saint-Ruf C, Gibson JL, Frisch RL, Lichtarge O, Hastings PJ, Rosenberg SM (2012). "Identity and function of a large gene network underlying mutagenic repair of DNA breaks." Science 338(6112);1344-8. PMID: 23224554
Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554
Berks00: Berks BC, Sargent F, De Leeuw E, Hinsley AP, Stanley NR, Jack RL, Buchanan G, Palmer T (2000). "A novel protein transport system involved in the biogenesis of bacterial electron transfer chains." Biochim Biophys Acta 1459(2-3);325-30. PMID: 11004447
Bogsch98: Bogsch EG, Sargent F, Stanley NR, Berks BC, Robinson C, Palmer T (1998). "An essential component of a novel bacterial protein export system with homologues in plastids and mitochondria." J Biol Chem 273(29);18003-6. PMID: 9660752
Bolhuis01: Bolhuis A, Mathers JE, Thomas JD, Barrett CM, Robinson C (2001). "TatB and TatC form a functional and structural unit of the twin-arginine translocase from Escherichia coli." J Biol Chem 276(23);20213-9. PMID: 11279240
Buchanan02: Buchanan G, de Leeuw E, Stanley NR, Wexler M, Berks BC, Sargent F, Palmer T (2002). "Functional complexity of the twin-arginine translocase TatC component revealed by site-directed mutagenesis." Mol Microbiol 43(6);1457-70. PMID: 11952898
De01a: De Leeuw E, Porcelli I, Sargent F, Palmer T, Berks BC (2001). "Membrane interactions and self-association of the TatA and TatB components of the twin-arginine translocation pathway." FEBS Lett 506(2);143-8. PMID: 11591389
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Drew02: Drew D, Sjostrand D, Nilsson J, Urbig T, Chin CN, de Gier JW, von Heijne G (2002). "Rapid topology mapping of Escherichia coli inner-membrane proteins by prediction and PhoA/GFP fusion analysis." Proc Natl Acad Sci U S A 99(5);2690-5. PMID: 11867724
Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938
Huerta03: Huerta AM, Collado-Vides J (2003). "Sigma70 promoters in Escherichia coli: specific transcription in dense regions of overlapping promoter-like signals." J Mol Biol 333(2);261-78. PMID: 14529615
Ize02: Ize B, Gerard F, Zhang M, Chanal A, Voulhoux R, Palmer T, Filloux A, Wu LF (2002). "In vivo dissection of the Tat translocation pathway in Escherichia coli." J Mol Biol 317(3);327-35. PMID: 11922668
Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394
Kostecki10: Kostecki JS, Li H, Turner RJ, DeLisa MP (2010). "Visualizing interactions along the Escherichia coli twin-arginine translocation pathway using protein fragment complementation." PLoS One 5(2);e9225. PMID: 20169075
Maldonado11: Maldonado B, Buchanan G, Muller M, Berks BC, Palmer T (2011). "Genetic Evidence for a TatC Dimer at the Core of the Escherichia coli Twin Arginine (Tat) Protein Translocase." J Mol Microbiol Biotechnol 20(3);168-75. PMID: 21709427
Maldonado11a: Maldonado B, Kneuper H, Buchanan G, Hatzixanthis K, Sargent F, Berks BC, Palmer T (2011). "Characterisation of the membrane-extrinsic domain of the TatB component of the twin arginine protein translocase." FEBS Lett 585(3);478-84. PMID: 21237157
Marrichi08: Marrichi MJ, Camacho L, Russell DG, Delisa MP (2008). "Genetic toggling of alkaline phosphatase folding reveals signal peptides for all major modes of transport across the inner membrane of bacteria." J Biol Chem 283(50):35223-35. PMID: 18819916
Mould91: Mould RM, Robinson C (1991). "A proton gradient is required for the transport of two lumenal oxygen-evolving proteins across the thylakoid membrane." J Biol Chem 266(19);12189-93. PMID: 1648086
Rapp04: Rapp M, Drew D, Daley DO, Nilsson J, Carvalho T, Melen K, De Gier JW, Von Heijne G (2004). "Experimentally based topology models for E. coli inner membrane proteins." Protein Sci 13(4);937-45. PMID: 15044727
Santini01: Santini CL, Bernadac A, Zhang M, Chanal A, Ize B, Blanco C, Wu LF (2001). "Translocation of jellyfish green fluorescent protein via the Tat system of Escherichia coli and change of its periplasmic localization in response to osmotic up-shock." J Biol Chem 276(11);8159-64. PMID: 11099493
Sargent01: Sargent F, Gohlke U, De Leeuw E, Stanley NR, Palmer T, Saibil HR, Berks BC (2001). "Purified components of the Escherichia coli Tat protein transport system form a double-layered ring structure." Eur J Biochem 268(12);3361-7. PMID: 11422364
Sargent98: Sargent F, Bogsch EG, Stanley NR, Wexler M, Robinson C, Berks BC, Palmer T (1998). "Overlapping functions of components of a bacterial Sec-independent protein export pathway." EMBO J 17(13);3640-50. PMID: 9649434
Tarry09: Tarry MJ, Schafer E, Chen S, Buchanan G, Greene NP, Lea SM, Palmer T, Saibil HR, Berks BC (2009). "Structural analysis of substrate binding by the TatBC component of the twin-arginine protein transport system." Proc Natl Acad Sci U S A 106(32);13284-9. PMID: 19666509
Weiner98: Weiner JH, Bilous PT, Shaw GM, Lubitz SP, Frost L, Thomas GH, Cole JA, Turner RJ (1998). "A novel and ubiquitous system for membrane targeting and secretion of cofactor-containing proteins." Cell 93(1);93-101. PMID: 9546395
Wexler00: Wexler M, Sargent F, Jack RL, Stanley NR, Bogsch EG, Robinson C, Berks BC, Palmer T (2000). "TatD is a cytoplasmic protein with DNase activity. No requirement for TatD family proteins in sec-independent protein export." J Biol Chem 2000;275(22);16717-22. PMID: 10747959
Zhang07: Zhang N, Chen R, Young N, Wishart D, Winter P, Weiner JH, Li L (2007). "Comparison of SDS- and methanol-assisted protein solubilization and digestion methods for Escherichia coli membrane proteome analysis by 2-D LC-MS/MS." Proteomics 7(4);484-93. PMID: 17309111
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