|Gene:||pspA||Accession Numbers: EG10776 (EcoCyc), b1304, ECK1299|
PspA is a negative transcriptional regulator of the psp operon [Weiner91] that does not directly interact with DNA [Dworkin00]. PspA regulates the activity of the catalytic PspF AAA domain via a direct interaction that affects nucleotide binding [Elderkin02, Joly09]. PspA involvement in protein export [Kleerebezem93] is due to its role in maintenance of the protonmotive force under certain conditions of cellular stress [Kleerebezem96].
PspA is a peripheral [Kleerebezem93] inner membrane protein [Brissette91, Bergler94]. PspA, PspB, and PspC form a complex, and PspC is required for PspA to bind to PspB [Adams03]. PspA, PspB, and PspC are not observed to cross-link with PspD [Adams03].
PspA is predicted to form a coiled-coil structure, based on its heptad repeat motif [Brissette91]. Three-dimensional reconstruction of a PspA complex revealed a 9-fold rotationally symmetric ring; the nine domains are predicted to be composed of four individual PspA subunits [Hankamer04]. The protein is subject to post-translational modification [Brissette91].
A pspABC mutant exhibits a defect in long-term survival of stationary phase in high pH media and a defect in competition with wild-type strains under these conditions [Weiner94]. A mutant shows defects in protein translocation [Kleerebezem93, Kleerebezem96]. Multi-copy overexpression of the psp operon increases survival of stress caused by n-hexane treatment [Kobayashi98]. Overexpression of pspA on a multicopy plasmid improved the efficiency of protein export by the Tat system [DeLisa04].
The cog-192 mutation causes deletion of several genes and causes ompG transcription to be directed by the pspA promoter [Fajardo98]. A cog-192 mutation causes the following recessive phenotypes: increased production of OmpG and maltodextrin utilization in a mutant defective in uptake of maltodextrin via the LamB, and PspA is therefore suggested to be involved in OmpG regulation [Misra89].
Regulation has been described [Dworkin97, Dworkin98, Jovanovic99, Carmona99]. The psp operon shows induction upon phage infection, temperature increase, osmotic shock, or exposure to ethanol [Brissette91] or the organic solvents n-hexane or cyclooctane [Kobayashi98]. Induction is mediated by σ54, PspB, PspC [Weiner91], PspF [Jovanovic96], and IHF [Weiner95]. Transcription is induced by conditions that cause stress related to energy depletion [Weiner94]. Treatment with the drugs diazaborine or cerulenin, which inhibit synthesis of fatty acids and phospholipids, or treatment with globomycin, which disrupts lipoprotein processing, causes transcriptional induction of pspA [Bergler94]. PspA production is also increased when protein export is compromised [Kleerebezem93, Hardie96]. Transcription is repressed by PspA and by the heat shock (σ32-dependent) system [Weiner91].
PspA: phage shock protein A [Brissette91]
Cog: control of ompG [Misra89]
Gene Citations: [Fozo08]
Locations: cytosol, inner membrane
|Map Position: [1,366,103 -> 1,366,771] (29.44 centisomes)||Length: 669 bp / 222 aa|
Unification Links: ASAP:ABE-0004387 , CGSC:32009 , EchoBASE:EB0769 , EcoGene:EG10776 , EcoliWiki:b1304 , OU-Microarray:b1304 , PortEco:pspA , PR:PRO_000023614 , Pride:P0AFM6 , Protein Model Portal:P0AFM6 , RefSeq:NP_415820 , RegulonDB:EG10776 , String:511145.b1304 , UniProt:P0AFM6
|Biological Process:||GO:0009271 - phage shock
GO:0009408 - response to heat [Chuang93]
GO:0006950 - response to stress [UniProtGOA11]
|Cellular Component:||GO:0005829 - cytosol
GO:0005737 - cytoplasm [UniProtGOA11a, UniProtGOA11]
GO:0005886 - plasma membrane [UniProtGOA11a, UniProtGOA11]
GO:0016020 - membrane [UniProtGOA11]
|MultiFun Terms:||extrachromosomal → prophage genes and phage related functions|
|information transfer → RNA related → Transcription related|
|regulation → genetic unit regulated → operon|
|regulation → type of regulation → transcriptional level → repressor|
|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]|
|Chain||2 -> 222|
10/20/97 Gene b1304 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10776; confirmed by SwissProt match.
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
DeLisa04: DeLisa MP, Lee P, Palmer T, Georgiou G (2004). "Phage shock protein PspA of Escherichia coli relieves saturation of protein export via the Tat pathway." J Bacteriol 186(2);366-73. PMID: 14702305
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
Dworkin97: Dworkin J, Jovanovic G, Model P (1997). "Role of upstream activation sequences and integration host factor in transcriptional activation by the constitutively active prokaryotic enhancer-binding protein PspF." J Mol Biol 273(2);377-88. PMID: 9344746
Elderkin02: Elderkin S, Jones S, Schumacher J, Studholme D, Buck M (2002). "Mechanism of action of the Escherichia coli phage shock protein PspA in repression of the AAA family transcription factor PspF." J Mol Biol 2002;320(1);23-37. PMID: 12079332
Fajardo98: Fajardo DA, Cheung J, Ito C, Sugawara E, Nikaido H, Misra R (1998). "Biochemistry and regulation of a novel Escherichia coli K-12 porin protein, OmpG, which produces unusually large channels." J Bacteriol 1998;180(17);4452-9. PMID: 9721282
Fozo08: Fozo EM, Kawano M, Fontaine F, Kaya Y, Mendieta KS, Jones KL, Ocampo A, Rudd KE, Storz G (2008). "Repression of small toxic protein synthesis by the Sib and OhsC small RNAs." Mol Microbiol 70(5):1076-93. PMID: 18710431
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
Joly09: Joly N, Burrows PC, Engl C, Jovanovic G, Buck M (2009). "A lower-order oligomer form of phage shock protein A (PspA) stably associates with the hexameric AAA(+) transcription activator protein PspF for negative regulation." J Mol Biol 394(4);764-75. PMID: 19804784
Jovanovic96: Jovanovic G, Weiner L, Model P (1996). "Identification, nucleotide sequence, and characterization of PspF, the transcriptional activator of the Escherichia coli stress-induced psp operon." J Bacteriol 178(7);1936-45. PMID: 8606168
Jovanovic99: Jovanovic G, Rakonjac J, Model P (1999). "In vivo and in vitro activities of the Escherichia coli sigma54 transcription activator, PspF, and its DNA-binding mutant, PspFDeltaHTH." J Mol Biol 285(2);469-83. PMID: 9878422
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
Kleerebezem96: Kleerebezem M, Crielaard W, Tommassen J (1996). "Involvement of stress protein PspA (phage shock protein A) of Escherichia coli in maintenance of the protonmotive force under stress conditions." EMBO J 1996;15(1);162-71. PMID: 8598199
Kobayashi98: Kobayashi H, Yamamoto M, Aono R (1998). "Appearance of a stress-response protein, phage-shock protein A, in Escherichia coli exposed to hydrophobic organic solvents." Microbiology 144 ( Pt 2);353-9. PMID: 9493373
Weiner91: Weiner L, Brissette JL, Model P (1991). "Stress-induced expression of the Escherichia coli phage shock protein operon is dependent on sigma 54 and modulated by positive and negative feedback mechanisms." Genes Dev 5(10);1912-23. PMID: 1717346
Weiner95: Weiner L, Brissette JL, Ramani N, Model P (1995). "Analysis of the proteins and cis-acting elements regulating the stress-induced phage shock protein operon." Nucleic Acids Res 23(11);2030-6. PMID: 7596833
Hou12: Hou Z, Fink RC, Black EP, Sugawara M, Zhang Z, Diez-Gonzalez F, Sadowsky MJ (2012). "Gene expression profiling of Escherichia coli in response to interactions with the lettuce rhizosphere." J Appl Microbiol 113(5);1076-86. PMID: 22830299
Huvet11: Huvet M, Toni T, Sheng X, Thorne T, Jovanovic G, Engl C, Buck M, Pinney JW, Stumpf MP (2011). "The evolution of the phage shock protein response system: interplay between protein function, genomic organization, and system function." Mol Biol Evol 28(3);1141-55. PMID: 21059793
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