|Gene:||slp||Accession Numbers: EG11890 (EcoCyc), b3506, ECK3490|
Slp (starvation lipoprotein) is the product of the slp gene [Alexander94] which forms an operon with the downstream gene dctR [Tucker03]. Slp is believed to take part in acid resistance as expression increased when cells were grown at pH 5.5 and 4.5 under conditions known to induce glutamate-dependent acid resistance compared to pH 7.4 under the same conditions [Tucker02]. During growth in acidic conditions, expression of Slp is negatively regulated by GadW, but positively regulated by GadXW, which are regulators of the two glutamate decarboxylase genes and the GABA APC transporter responsible for glutamate-dependent acid resistance [Tucker03]. slp is highly induced by overexpression of EvgA [Masuda02], [Nishino03] indirectly through its induction of YdeO expression [Ma04], though slp was found to have a putative EvgA binding motif 542 base pairs upstream of its start codon [Nishino03].
Under certain conditions, deletion of slp-dctR resulted in reduction of YdeO-induced acid resistance [Masuda03], though under conditions used to induce acid resistance naturally, slp-dctR was not necessary [Ma04]. A slp-dctR double mutant exhibited loss of viability during growth in spent LB at pH 2.5 much faster than wild-type [Mates07]. The slp-dctR double mutant was also unable to survive at pH 2.5 in minimal medium when formate, succinate, or lactate were added [Mates07]. The fact that individual slp and dctR mutants retain resistance indicates redundant functions for Slp and DctR in protection against formate, succinate, and lactate at low pH [Mates07].
slp is upregulated when cells are deprived of carbon or during stationary phase [Alexander94]. Expression of slp increases 3-5 fold in stationary phase [Shimada04]. This has been shown under certain conditions to occur independently of RpoS, cAMP, and DnaK [Alexander94], while under other conditions the promoter for slp is RpoS sigma-dependent [Shimada04]. Expression of slp is reduced after 10 hours of nitrogen starvation in an rpoS mutant [Kabir04a]. Sequence analysis suggests slp may also be controlled by a sigma 70 promoter [Alexander94].
Slp expression is reduced by constitutive expression of marRAB, which is responsible for multiple antibiotic resistance [Seoane95a]. The Mar system affects Slp expression during the transition from exponential to stationary phase, though not the final stationary phase level. Cells show some increased chloramphenicol sensitivity when Slp levels increase [Price00].
The level of Slp expression increased in response to exposure to acetate [Arnold01] and acivicin [Smulski01], in the presence of the transcriptional regulator SlyA in the enteroinvasive E. coli strain 12860 [Spory02], when the leucine-responsive regulatory protein is not expressed [Tani02], and upon deletion of hns, encoding the H-NS transcriptional duel regulator [Nishino04]. Slp is strongly induced under anaerobic growth, but repression occurs after addition of nitrate [Brokx04]. Other factors that reduce Slp expression include filamentous phage infection [Karlsson05], adhesion of cells to abiotic surfaces [Otto01], and the expression of SulA, though this is suggested to be more likely the result of a response to physiological alterations due to blockage of cell division [Arends04].
Slp was found as higher order oligomers tethered to the outer membrane [Stenberg05].
Locations: outer membrane
|Map Position: [3,651,984 -> 3,652,550] (78.71 centisomes)||Length: 567 bp / 188 aa|
Molecular Weight of Polypeptide: 20.964 kD (from nucleotide sequence), 22 kD (experimental) [Alexander94 ]
Unification Links: ASAP:ABE-0011451 , CGSC:33726 , EchoBASE:EB1836 , EcoGene:EG11890 , EcoliWiki:b3506 , OU-Microarray:b3506 , PortEco:slp , PR:PRO_000023955 , Pride:P37194 , Protein Model Portal:P37194 , RefSeq:NP_417963 , RegulonDB:EG11890 , String:511145.b3506 , UniProt:P37194
In Paralogous Gene Group: 534 (2 members)
|Molecular Function:||GO:0042802 - identical protein binding [Rajagopala14, Stenberg05]|
|Cellular Component:||GO:0019867 - outer membrane
GO:0009279 - cell outer membrane [UniProtGOA11, UniProtGOA11a, Alexander94]
GO:0016020 - membrane [UniProtGOA11a]
|MultiFun Terms:||cell processes → adaptations → starvation|
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB Lennox||Yes||37||Aerobic||7||Yes [Baba06, Comment 1]|
|M9 medium with 1% glycerol||Yes||37||Aerobic||7.2||0.35||Yes [Joyce06, Comment 2]|
|MOPS medium with 0.4% glucose||Yes||37||Aerobic||7.2||0.22||Yes [Baba06, Comment 1]|
|Signal-Sequence||1 -> 18|
|Chain||19 -> 188|
Martin Peralta on Fri Oct 29, 2004:
The start site of this gene was originally assigned solely on the basis of sequence considerations (Blattner et al, 1997, [Blattner97 ]. However, it was changed because Alexander et al (1994) attested that the real start site is actually located in another position [Alexander94 ]. The demonstration is based on (a) comparisons of the new gene sequence with homologous proteins, (b) determination of the mRNA size (Northern blot), plus (c) identification of both a plausible ribosome binding site and a promoter at an appropriate distance from the new start site. The promoter was identified using primer extension analysis.
1/26/1998 (pkarp) Merged genes G7973/slp and EG11890/slp
Alexander94: Alexander DM, St John AC (1994). "Characterization of the carbon starvation-inducible and stationary phase-inducible gene slp encoding an outer membrane lipoprotein in Escherichia coli." Mol Microbiol 1994;11(6);1059-71. PMID: 8022277
Arnold01: Arnold CN, McElhanon J, Lee A, Leonhart R, Siegele DA (2001). "Global analysis of Escherichia coli gene expression during the acetate-induced acid tolerance response." J Bacteriol 183(7);2178-86. PMID: 11244055
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
Blattner97: Blattner FR, Plunkett G, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y (1997). "The complete genome sequence of Escherichia coli K-12." Science 277(5331);1453-74. PMID: 9278503
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
Kabir04a: Kabir MS, Sagara T, Oshima T, Kawagoe Y, Mori H, Tsunedomi R, Yamada M (2004). "Effects of mutations in the rpoS gene on cell viability and global gene expression under nitrogen starvation in Escherichia coli." Microbiology 150(Pt 8);2543-53. PMID: 15289551
Karlsson05: Karlsson F, Malmborg-Hager AC, Albrekt AS, Borrebaeck CA (2005). "Genome-wide comparison of phage M13-infected vs. uninfected Escherichia coli." Can J Microbiol 51(1);29-35. PMID: 15782232
Ma04: Ma Z, Masuda N, Foster JW (2004). "Characterization of EvgAS-YdeO-GadE branched regulatory circuit governing glutamate-dependent acid resistance in Escherichia coli." J Bacteriol 186(21);7378-89. PMID: 15489450
Mates07: Mates AK, Sayad AK, Foster JW (2007). "Products of the Escherichia coli Acid Fitness Island Attenuate Metabolite Stress at Extreme Low pH and Mediate a Cell Density-Dependent Acid Resistance." J Bacteriol 189(7):2759-68. PMID: 17259322
Nishino03: Nishino K, Inazumi Y, Yamaguchi A (2003). "Global analysis of genes regulated by EvgA of the two-component regulatory system in Escherichia coli." J Bacteriol 185(8);2667-72. PMID: 12670992
Otto01: Otto K, Norbeck J, Larsson T, Karlsson KA, Hermansson M (2001). "Adhesion of type 1-fimbriated Escherichia coli to abiotic surfaces leads to altered composition of outer membrane proteins." J Bacteriol 183(8);2445-53. PMID: 11274103
Price00: Price GP, St John AC (2000). "Purification and analysis of expression of the stationary phase-inducible slp lipoprotein in Escherichia coli: role of the Mar system." FEMS Microbiol Lett 193(1);51-6. PMID: 11094278
Rajagopala14: Rajagopala SV, Sikorski P, Kumar A, Mosca R, Vlasblom J, Arnold R, Franca-Koh J, Pakala SB, Phanse S, Ceol A, Hauser R, Siszler G, Wuchty S, Emili A, Babu M, Aloy P, Pieper R, Uetz P (2014). "The binary protein-protein interaction landscape of Escherichia coli." Nat Biotechnol 32(3);285-90. PMID: 24561554
Shimada04: Shimada T, Makinoshima H, Ogawa Y, Miki T, Maeda M, Ishihama A (2004). "Classification and strength measurement of stationary-phase promoters by use of a newly developed promoter cloning vector." J Bacteriol 186(21);7112-22. PMID: 15489422
Smulski01: Smulski DR, Huang LL, McCluskey MP, Reeve MJ, Vollmer AC, Van Dyk TK, LaRossa RA (2001). "Combined, functional genomic-biochemical approach to intermediary metabolism: interaction of acivicin, a glutamine amidotransferase inhibitor, with Escherichia coli K-12." J Bacteriol 183(11);3353-64. PMID: 11344143
Spory02: Spory A, Bosserhoff A, von Rhein C, Goebel W, Ludwig A (2002). "Differential regulation of multiple proteins of Escherichia coli and Salmonella enterica serovar Typhimurium by the transcriptional regulator SlyA." J Bacteriol 2002;184(13);3549-59. PMID: 12057949
Stenberg05: Stenberg F, Chovanec P, Maslen SL, Robinson CV, Ilag LL, von Heijne G, Daley DO (2005). "Protein complexes of the Escherichia coli cell envelope." J Biol Chem 280(41);34409-19. PMID: 16079137
Tani02: Tani TH, Khodursky A, Blumenthal RM, Brown PO, Matthews RG (2002). "Adaptation to famine: a family of stationary-phase genes revealed by microarray analysis." Proc Natl Acad Sci U S A 99(21);13471-6. PMID: 12374860
Johnson11: Johnson MD, Burton NA, Gutierrez B, Painter K, Lund PA (2011). "RcsB Is Required for Inducible Acid Resistance in Escherichia coli and Acts at gadE-Dependent and -Independent Promoters." J Bacteriol 193(14);3653-6. PMID: 21571995
Krin10a: Krin E, Danchin A, Soutourina O (2010). "RcsB plays a central role in H-NS-dependent regulation of motility and acid stress resistance in Escherichia coli." Res Microbiol 161(5);363-371. PMID: 20435136
Tramonti08: Tramonti A, De Canio M, De Biase D (2008). "GadX/GadW-dependent regulation of the Escherichia coli acid fitness island: transcriptional control at the gadY-gadW divergent promoters and identification of four novel 42 bp GadX/GadW-specific binding sites." Mol Microbiol 70(4);965-82. PMID: 18808381
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