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Escherichia coli K-12 substr. MG1655 Polypeptide: putative protein secretion protein

Gene: gspM Accession Numbers: EG12173 (EcoCyc), b3334, ECK3321

Synonyms: hopZ, pshM

Regulation Summary Diagram

Regulation summary diagram for gspM

Component of: GspC-O secreton complex (extended summary available)

In Escherichia coli, gspM is a member of an operon of genes (gspC-O) which are not normally expressed [Francetic00] but are homologous to those encoding the secreton, or type II secretion machinery in Klebsiella oxytoca and Aeromonase hydrophila, among others [Francetic96]. GspM, an inner membrane protein [Sandkvist01], has been shown, in coimmunoprecipitation studies, to interact with GspC, GspE and GspL in the formation of heterooligomers [Py01], [Possot00], [Sandkvist00].

GspM homologs have been characterized in Helicobacter pylori [Peck99, Guo01, Bai02, Yamaoka02, Lehours04] and in Erwinia chrysanthemi [Py01]. HopZ of Helicobacter pylori is required for wild-type adhesion [Peck99]. GspM of Erwinia chrysanthemi is an inner membrane protein involved in maturation of the type II secretion complex [Py01].

Locations: extracellular space, inner membrane

Map Position: [3,463,104 -> 3,463,565] (74.64 centisomes, 269°)
Length: 462 bp / 153 aa

Molecular Weight of Polypeptide: 17.234 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0010898, EchoBASE:EB2091, EcoGene:EG12173, EcoliWiki:b3334, OU-Microarray:b3334, PortEco:gspM, Pride:P36678, Protein Model Portal:P36678, RefSeq:NP_417793, RegulonDB:EG12173, String:511145.b3334, UniProt:P36678

Relationship Links: InterPro:IN-FAMILY:IPR007690, InterPro:IN-FAMILY:IPR023229, Pfam:IN-FAMILY:PF04612

Gene-Reaction Schematic

Gene-Reaction Schematic

Genetic Regulation Schematic

Genetic regulation schematic for gspM

GO Terms:
Biological Process:
Inferred by computational analysisGO:0006810 - transport [UniProtGOA11a]
Inferred by computational analysisGO:0006858 - extracellular transport [GOA01a]
Inferred by computational analysisGO:0015031 - protein transport [UniProtGOA11a]
Cellular Component:
Inferred by computational analysisGO:0005576 - extracellular region [GOA01a]
Inferred by computational analysisGO:0005886 - plasma membrane [UniProtGOA11, UniProtGOA11a, Sandkvist01]
Inferred by computational analysisGO:0016020 - membrane [UniProtGOA11a]
Inferred by computational analysisGO:0016021 - integral component of membrane [UniProtGOA11a]

MultiFun Terms: All-GenesPseudo-GenesCryptic-Genes
MultiFuntransportPutative uncharacterized transport protein

Essentiality data for gspM knockouts:

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB LennoxYes 37 Aerobic 7   Yes [Baba06, Comment 1]
M9 medium with 1% glycerolYes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 2]
MOPS medium with 0.4% glucoseYes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 1]

Subunit of: GspC-O secreton complex

Inferred from experiment

Subunit composition of GspC-O secreton complex = [GspC][GspD][GspE][GspF][GspG][GspH][GspI][GspJ][GspK][GspL][GspM][GspO]
         putative protein secretion protein for export = GspC (summary available)
         putative protein secretion protein for export = GspD (summary available)
         putative protein secretion protein for export = GspE (extended summary available)
         putative protein secretion protein for export = GspF (summary available)
         putative protein secretion protein for export = GspG (summary available)
         putative protein secretion protein for export = GspH (summary available)
         putative protein secretion protein for export = GspI (summary available)
         putative protein secretion protein for export = GspJ (summary available)
         putative protein secretion protein for export = GspK (summary available)
         putative protein secretion protein for export = GspL (summary available)
         putative protein secretion protein = GspM (summary available)
         leader peptidase, integral membrane protein = GspO (extended summary available)

GspC-O, the type II secretion or secreton complex in Escherichia coli has also been known as the general secretory pathway (GSP) for the export of proteins across the outer membranes of gram-negative bacteria [Pugsley93]. Translocation across the cytoplasmic membrane prior to secreton-dependent secretion can take place via the signal peptide-dependent Sec pathway or the twin-arginine translocation (TAT) system [Voulhoux01]. After transport across the outer membrane, the translocated proteins may be either released into the medium or stay attached to the outer membrane and assembled into surface organelles [Pugsley93, Pugsley98]. The secreton facilitates the extrusion of folded proteins through a putative large gated pore in the outer membrane [Pugsley93]. Although Escherichia coli K-12 does not secrete endogenous proteins, the gsp genes of E. coli are orthologs of those in other secretons [Francetic96], including those of the pullulanase (pul) secretion pathway of Klebsiella oxytoca. The pulO gene product has been shown to be an enzyme required for processing of PulG as well as PulH, PulI and PulJ [Pugsley93a, Strom94]. Complementation studies have shown that the pulO homolog, gspO, is capable of complementing the processing function in a pulO deletion mutant [Francetic96]. The pulG homolog, gspG, has been shown to be capable of complementing a pulG mutation when expressed under the control of a lac promoter [Francetic96]. Transcription of the gspC-O operon was shown to be silenced in wild-type E. coli K-12 by the nucleoid structuring protein H-NS. Deletion mutants lacking H-NS and with the gsp genes present on a multiple-copy-number plasmid have been shown to express the secreton genes and promote the efficient secretion of the co-regulated endochitinase ChiA [Francetic00]. Expression of gspC-O also resulted in formation of pili composed of the GspG pseudopilin when extra copies of gspG were supplied on a second plasmid [Vignon03].

Sequence Features

Protein sequence of putative protein secretion protein with features indicated

Feature Class Location Citations Comment
Pfam PF04612 2 -> 150
Inferred by computational analysis[Finn14]
T2SSM : Type II secretion system (T2SS), protein M
Transmembrane-Region 17 -> 37
Inferred by computational analysis[UniProt15]
UniProt: Helical.

Gene Local Context (not to scale -- see Genome Browser for correct scale)

Gene local context diagram

Transcription Units

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram


Peter D. Karp on Wed Jan 18, 2006:
Gene left-end position adjusted based on analysis performed in the 2005 E. coli annotation update [Riley06].
10/20/97 Gene b3334 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG12173; 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

Bai02: Bai Y, Zhang YL, Wang JD, Lin HJ, Zhang ZS, Zhou DY (2002). "Conservative region of the genes encoding four adhesins of Helicobacter pylori: cloning, sequence analysis and biological information analysis." Di Yi Jun Yi Da Xue Xue Bao 22(10);869-71. PMID: 12377603

Finn14: Finn RD, Bateman A, Clements J, Coggill P, Eberhardt RY, Eddy SR, Heger A, Hetherington K, Holm L, Mistry J, Sonnhammer EL, Tate J, Punta M (2014). "Pfam: the protein families database." Nucleic Acids Res 42(Database issue);D222-30. PMID: 24288371

Francetic00: Francetic O, Belin D, Badaut C, Pugsley AP (2000). "Expression of the endogenous type II secretion pathway in Escherichia coli leads to chitinase secretion." EMBO J 19(24);6697-703. PMID: 11118204

Francetic96: Francetic O, Pugsley AP (1996). "The cryptic general secretory pathway (gsp) operon of Escherichia coli K-12 encodes functional proteins." J Bacteriol 178(12);3544-9. PMID: 8655552

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

Guo01: Guo BP, Mekalanos JJ (2001). "Helicobacter pylori mutagenesis by mariner in vitro transposition." FEMS Immunol Med Microbiol 30(2);87-93. PMID: 11267839

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

Lehours04: Lehours P, Menard A, Dupouy S, Bergey B, Richy F, Zerbib F, Ruskone-Fourmestraux A, Delchier JC, Megraud F (2004). "Evaluation of the association of nine Helicobacter pylori virulence factors with strains involved in low-grade gastric mucosa-associated lymphoid tissue lymphoma." Infect Immun 72(2);880-8. PMID: 14742532

Peck99: Peck B, Ortkamp M, Diehl KD, Hundt E, Knapp B (1999). "Conservation, localization and expression of HopZ, a protein involved in adhesion of Helicobacter pylori." Nucleic Acids Res 27(16);3325-33. PMID: 10454640

Possot00: Possot OM, Vignon G, Bomchil N, Ebel F, Pugsley AP (2000). "Multiple interactions between pullulanase secreton components involved in stabilization and cytoplasmic membrane association of PulE." J Bacteriol 182(8);2142-52. PMID: 10735856

Pugsley93: Pugsley AP (1993). "The complete general secretory pathway in gram-negative bacteria." Microbiol Rev 57(1);50-108. PMID: 8096622

Pugsley93a: Pugsley AP (1993). "Processing and methylation of PuIG, a pilin-like component of the general secretory pathway of Klebsiella oxytoca." Mol Microbiol 9(2);295-308. PMID: 8412682

Pugsley98: Pugsley AP, Francetic O (1998). "Protein secretion in Escherichia coli K-12: dead or alive?." Cell Mol Life Sci 54(4);347-52. PMID: 9614971

Py01: Py B, Loiseau L, Barras F (2001). "An inner membrane platform in the type II secretion machinery of Gram-negative bacteria." EMBO Rep 2(3);244-8. PMID: 11266368

Riley06: Riley M, Abe T, Arnaud MB, Berlyn MK, Blattner FR, Chaudhuri RR, Glasner JD, Horiuchi T, Keseler IM, Kosuge T, Mori H, Perna NT, Plunkett G, Rudd KE, Serres MH, Thomas GH, Thomson NR, Wishart D, Wanner BL (2006). "Escherichia coli K-12: a cooperatively developed annotation snapshot--2005." Nucleic Acids Res 34(1);1-9. PMID: 16397293

Sandkvist00: Sandkvist M, Keith JM, Bagdasarian M, Howard SP (2000). "Two regions of EpsL involved in species-specific protein-protein interactions with EpsE and EpsM of the general secretion pathway in Vibrio cholerae." J Bacteriol 182(3);742-8. PMID: 10633109

Sandkvist01: Sandkvist M (2001). "Biology of type II secretion." Mol Microbiol 40(2);271-83. PMID: 11309111

Strom94: Strom MS, Nunn DN, Lory S (1994). "Posttranslational processing of type IV prepilin and homologs by PilD of Pseudomonas aeruginosa." Methods Enzymol 235;527-40. PMID: 8057924

UniProt15: UniProt Consortium (2015). "UniProt version 2015-08 released on 2015-07-22." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

Vignon03: Vignon G, Kohler R, Larquet E, Giroux S, Prevost MC, Roux P, Pugsley AP (2003). "Type IV-like pili formed by the type II secreton: specificity, composition, bundling, polar localization, and surface presentation of peptides." J Bacteriol 185(11);3416-28. PMID: 12754241

Voulhoux01: Voulhoux R, Ball G, Ize B, Vasil ML, Lazdunski A, Wu LF, Filloux A (2001). "Involvement of the twin-arginine translocation system in protein secretion via the type II pathway." EMBO J 20(23);6735-41. PMID: 11726509

Yamaoka02: Yamaoka Y, Kita M, Kodama T, Imamura S, Ohno T, Sawai N, Ishimaru A, Imanishi J, Graham DY (2002). "Helicobacter pylori infection in mice: Role of outer membrane proteins in colonization and inflammation." Gastroenterology 123(6);1992-2004. PMID: 12454856

Other References Related to Gene Regulation

Chen07: Chen Z, Lewis KA, Shultzaberger RK, Lyakhov IG, Zheng M, Doan B, Storz G, Schneider TD (2007). "Discovery of Fur binding site clusters in Escherichia coli by information theory models." Nucleic Acids Res 35(20);6762-77. PMID: 17921503

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
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