SUBB_ECOLX
ID SUBB_ECOLX Reviewed; 141 AA.
AC Q6EZC3;
DT 28-MAR-2018, integrated into UniProtKB/Swiss-Prot.
DT 16-AUG-2004, sequence version 1.
DT 03-AUG-2022, entry version 40.
DE RecName: Full=Subtilase cytotoxin subunit B {ECO:0000303|PubMed:15226357};
DE Flags: Precursor;
GN Name=subB {ECO:0000303|PubMed:15226357};
OS Escherichia coli.
OG Plasmid megaplasmid pO113 {ECO:0000312|EMBL:AAT68784.1}.
OC Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC Enterobacteriaceae; Escherichia.
OX NCBI_TaxID=562;
RN [1] {ECO:0000312|EMBL:AAT68784.1}
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=O113:H21 / 98NK2 / STEC; PLASMID=megaplasmid pO113;
RX PubMed=11598075; DOI=10.1128/iai.69.11.6999-7009.2001;
RA Paton A.W., Srimanote P., Woodrow M.C., Paton J.C.;
RT "Characterization of Saa, a novel autoagglutinating adhesin produced by
RT locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli
RT strains that are virulent for humans.";
RL Infect. Immun. 69:6999-7009(2001).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, AND SUBCELLULAR LOCATION.
RC STRAIN=O29;
RX PubMed=17101670; DOI=10.1128/iai.01336-06;
RA Morinaga N., Yahiro K., Matsuura G., Watanabe M., Nomura F., Moss J.,
RA Noda M.;
RT "Two distinct cytotoxic activities of subtilase cytotoxin produced by
RT Shiga-toxigenic Escherichia coli.";
RL Infect. Immun. 75:488-496(2007).
RN [3]
RP PROTEIN SEQUENCE OF N-TERMINUS, FUNCTION, SUBUNIT, SUBCELLULAR LOCATION,
RP OPERON, AND DISRUPTION PHENOTYPE.
RC STRAIN=O113:H21 / 98NK2 / STEC; PLASMID=megaplasmid pO113;
RX PubMed=15226357; DOI=10.1084/jem.20040392;
RA Paton A.W., Srimanote P., Talbot U.M., Wang H., Paton J.C.;
RT "A new family of potent AB(5) cytotoxins produced by Shiga toxigenic
RT Escherichia coli.";
RL J. Exp. Med. 200:35-46(2004).
RN [4]
RP ERRATUM OF PUBMED:15226357.
RX DOI=10.1084/jem.20040392111204c;
RA Paton A.W., Srimanote P., Talbot U.M., Wang H., Paton J.C.;
RT "A new family of potent AB(5) cytotoxins produced by Shiga toxigenic
RT Escherichia coli.";
RL J. Exp. Med. 200:1525-1525(2004).
RN [5]
RP FUNCTION, AND SUBCELLULAR LOCATION.
RX PubMed=17024087; DOI=10.1038/nature05124;
RA Paton A.W., Beddoe T., Thorpe C.M., Whisstock J.C., Wilce M.C.,
RA Rossjohn J., Talbot U.M., Paton J.C.;
RT "AB5 subtilase cytotoxin inactivates the endoplasmic reticulum chaperone
RT BiP.";
RL Nature 443:548-552(2006).
RN [6]
RP FUNCTION, AND SUBCELLULAR LOCATION.
RX PubMed=18042253; DOI=10.1111/j.1462-5822.2007.01085.x;
RA Chong D.C., Paton J.C., Thorpe C.M., Paton A.W.;
RT "Clathrin-dependent trafficking of subtilase cytotoxin, a novel AB5 toxin
RT that targets the endoplasmic reticulum chaperone BiP.";
RL Cell. Microbiol. 10:795-806(2008).
RN [7]
RP FUNCTION, AND SUBCELLULAR LOCATION.
RX PubMed=18005237; DOI=10.1111/j.1462-5822.2007.01094.x;
RA Morinaga N., Yahiro K., Matsuura G., Moss J., Noda M.;
RT "Subtilase cytotoxin, produced by Shiga-toxigenic Escherichia coli,
RT transiently inhibits protein synthesis of Vero cells via degradation of BiP
RT and induces cell cycle arrest at G1 by downregulation of cyclin D1.";
RL Cell. Microbiol. 10:921-929(2008).
RN [8]
RP FUNCTION.
RX PubMed=18433465; DOI=10.1111/j.1462-5822.2008.01164.x;
RA Wolfson J.J., May K.L., Thorpe C.M., Jandhyala D.M., Paton J.C.,
RA Paton A.W.;
RT "Subtilase cytotoxin activates PERK, IRE1 and ATF6 endoplasmic reticulum
RT stress-signalling pathways.";
RL Cell. Microbiol. 10:1775-1786(2008).
RN [9]
RP FUNCTION.
RX PubMed=19380466; DOI=10.1128/iai.01510-08;
RA Matsuura G., Morinaga N., Yahiro K., Komine R., Moss J., Yoshida H.,
RA Noda M.;
RT "Novel subtilase cytotoxin produced by Shiga-toxigenic Escherichia coli
RT induces apoptosis in Vero cells via mitochondrial membrane damage.";
RL Infect. Immun. 77:2919-2924(2009).
RN [10] {ECO:0007744|PDB:3DWA, ECO:0007744|PDB:3DWP, ECO:0007744|PDB:3DWQ}
RP X-RAY CRYSTALLOGRAPHY (2.08 ANGSTROMS) OF 24-141 IN COMPLEX WITH
RP N-GLYCOLOYL-ALPHA-NEURAMINIC ACID, SUBUNIT, MUTAGENESIS OF SER-35; GLN-59
RP AND TYR-101, AND GLYCAN-BINDING.
RX PubMed=18971931; DOI=10.1038/nature07428;
RA Byres E., Paton A.W., Paton J.C., Lofling J.C., Smith D.F., Wilce M.C.,
RA Talbot U.M., Chong D.C., Yu H., Huang S., Chen X., Varki N.M., Varki A.,
RA Rossjohn J., Beddoe T.;
RT "Incorporation of a non-human glycan mediates human susceptibility to a
RT bacterial toxin.";
RL Nature 456:648-652(2008).
RN [11] {ECO:0007744|PDB:4BWG}
RP X-RAY CRYSTALLOGRAPHY (2.60 ANGSTROMS) OF 24-141 IN COMPLEX WITH SUBA,
RP SUBUNIT, SUBCELLULAR LOCATION, DOMAIN, AND MUTAGENESIS OF VAL-38; TYR-89;
RP TYR-91; THR-92; GLY-94 AND GLN-95.
RX PubMed=23921389; DOI=10.1074/jbc.m113.462622;
RA Le Nours J., Paton A.W., Byres E., Troy S., Herdman B.P., Johnson M.D.,
RA Paton J.C., Rossjohn J., Beddoe T.;
RT "Structural basis of subtilase cytotoxin SubAB assembly.";
RL J. Biol. Chem. 288:27505-27516(2013).
CC -!- FUNCTION: Receptor-binding subunit of subtilase cytotoxin SubAB5.
CC Required for receptor-binding and thus correct trafficking in the host
CC cell (PubMed:18042253, PubMed:17024087). Has specificity for host
CC glycans terminating in the sialic acid N-glycolyl-alpha-neuraminic acid
CC (Neu5Gc); each subunit in the SubB pentamer binds one Neu5Gc
CC (PubMed:18971931). The protease subunit (SubA) cleaves host BiP/HSPA5,
CC inducing the host endoplasmic reticulum stress response and eventual
CC cell death (PubMed:18005237, PubMed:18433465). Culture supernatant of
CC E.coli expressing both subA and subB are toxic for Vero cells (African
CC green monkey kidney cell line), Chinese hamster ovary cells and Hct-8
CC cells (human colonic epithelial cell line); the subunits are not toxic
CC individually (PubMed:15226357). Purified SubAB5 is highly toxic, <0.1
CC pg is able to kill at least 50% of 30'000 Vero cells in a microtiter
CC plate assay after 3 days; no cytotoxicity is seen at 24 hours
CC (PubMed:15226357). Preabsorption with cells expressing a ganglioside
CC GM2 mimic reduced cytotoxicity of SubAB5 by 93% in the Vero
CC cytotoxicity assay (PubMed:15226357). Intraperitoneal injection of 200
CC ng of purified SubAB5 kills mice; the higher the dose the faster the
CC mice die. Animals injected with purified SubAB5 have microvascular
CC thrombi in the brain and other organs, including the renal tubules and
CC glomeruli. Mice fed E.coli cells expressing cloned SubAB5 experience
CC drastic weight loss and appear ill and lethargic (PubMed:15226357).
CC SubB alone at 2.5 ug/ml causes vacuolation of Vero cells, which
CC requires the V-type ATPase proton pump; treated cells die
CC (PubMed:17101670). Protein synthesis in Vero cells is transiently
CC inhibited by SubAB5; both subunits are required for this effect
CC (PubMed:17101670, PubMed:18005237, PubMed:18433465). Inhibition of
CC protein synthesis is prevented by brefeldin A; cells are arrested in
CC the G1 phase (PubMed:18005237). SubAB5 at 100 ng/ml induced caspase-
CC dependent apoptosis in Vero cells through mitochondrial membrane damage
CC (PubMed:19380466). {ECO:0000269|PubMed:15226357,
CC ECO:0000269|PubMed:17101670, ECO:0000269|PubMed:18005237,
CC ECO:0000269|PubMed:18042253, ECO:0000269|PubMed:18433465,
CC ECO:0000269|PubMed:18971931, ECO:0000269|PubMed:19380466,
CC ECO:0000305|PubMed:17024087}.
CC -!- SUBUNIT: Forms a complex with SubA with the stoichiometry SubA1:SubB5
CC (called SubAB5) (PubMed:15226357, PubMed:23921389). Each SubB subunit
CC makes different contacts with the single SubA subunit
CC (PubMed:23921389). This subunit alone forms pentamers
CC (PubMed:18971931). {ECO:0000269|PubMed:18971931,
CC ECO:0000269|PubMed:23921389, ECO:0000305|PubMed:15226357}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:15226357}. Host
CC cytoplasm, host cytosol {ECO:0000269|PubMed:15226357,
CC ECO:0000269|PubMed:17101670}. Host endoplasmic reticulum lumen
CC {ECO:0000305|PubMed:17024087, ECO:0000305|PubMed:18005237,
CC ECO:0000305|PubMed:23921389}. Note=Colocalizes with host BiP/HSPA5 in
CC the endoplasmic reticulum of Vero cells, its activity on BiP/HSPA5 is
CC blocked by pretreatment with brefeldin A, which disrupts the Golgi
CC apparatus and inhibits retrograde transport from the cell surface to
CC the Golgi (PubMed:17024087, PubMed:18005237). Using different
CC inhibitors it has been shown to be actively internalized by membrane-
CC bound vesicles and undergoes clathrin-dependent retrograde transport,
CC via early endosomes and the Golgi network, to the endoplasmic reticulum
CC (PubMed:18042253). Trafficking is similar in Vero cells, human HeLa
CC cells and murine N2A cells (PubMed:18042253).
CC {ECO:0000269|PubMed:15226357, ECO:0000269|PubMed:17024087,
CC ECO:0000269|PubMed:18005237, ECO:0000269|PubMed:18042253}.
CC -!- INDUCTION: Part of the subA-subB operon (PubMed:15226357).
CC {ECO:0000269|PubMed:15226357}.
CC -!- DOMAIN: A patch of hydrophobic and neutral of amino acids (residues 89-
CC 94) forms a ring around the central pore of the pentamer, which
CC interacts with the A2 helix of the SubA subunit; some mutations in this
CC patch prevent SubAB5 complex formation but still allow some targeting
CC to the host endoplasmic reticulum lumen (PubMed:23921389). One residue
CC in this patch, Thr-92, is the only residue that contacts SubA from all
CC 5 of the SubB subunits (PubMed:23921389).
CC {ECO:0000269|PubMed:23921389}.
CC -!- DISRUPTION PHENOTYPE: No longer toxic to CHO cells when deletion
CC construct is coexpressed with subA (PubMed:15226357).
CC {ECO:0000269|PubMed:15226357}.
CC -!- MISCELLANEOUS: The E.coli strain this operon was isolated from causes
CC hemolytic uremic syndrome (HUS) and also encodes a Shigella-type toxin
CC Stx. {ECO:0000303|PubMed:15226357}.
CC -!- MISCELLANEOUS: Humans cannot convert CMP-Neu5Ac to CMP-Neu5Gc due to a
CC mutation in the CMAHP gene, and so should be less susceptible to this
CC toxin than other animals. However Neu5Gc can be acquired from red meat
CC and milk products, resulting in Neu5Gc incorporation into human tissue
CC (PubMed:18971931). {ECO:0000303|PubMed:18971931}.
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DR EMBL; AF399919; AAT68784.1; -; Genomic_DNA.
DR PDB; 3DWA; X-ray; 2.08 A; A/B/C/D/E=24-141.
DR PDB; 3DWP; X-ray; 2.20 A; A/B/C/D/E=24-141.
DR PDB; 3DWQ; X-ray; 2.10 A; A/B/C/D/E=24-141.
DR PDB; 4BWG; X-ray; 2.60 A; B/C/D/E/F/H/I/J/K/L=24-141.
DR PDBsum; 3DWA; -.
DR PDBsum; 3DWP; -.
DR PDBsum; 3DWQ; -.
DR PDBsum; 4BWG; -.
DR AlphaFoldDB; Q6EZC3; -.
DR SMR; Q6EZC3; -.
DR UniLectin; Q6EZC3; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0044164; C:host cell cytosol; IEA:UniProtKB-SubCell.
DR GO; GO:0044166; C:host cell endoplasmic reticulum lumen; IMP:UniProtKB.
DR GO; GO:0033691; F:sialic acid binding; IDA:UniProtKB.
DR InterPro; IPR008992; Enterotoxin.
DR SUPFAM; SSF50203; SSF50203; 1.
PE 1: Evidence at protein level;
KW 3D-structure; Direct protein sequencing; Host cytoplasm;
KW Host endoplasmic reticulum; Plasmid; Secreted; Signal; Virulence.
FT SIGNAL 1..23
FT /evidence="ECO:0000255, ECO:0000305|PubMed:15226357"
FT CHAIN 24..141
FT /note="Subtilase cytotoxin subunit B"
FT /evidence="ECO:0000255"
FT /id="PRO_5004273050"
FT REGION 89..94
FT /note="Hydrophobic patch important for binding to SubA"
FT /evidence="ECO:0000269|PubMed:23921389"
FT BINDING 33..35
FT /ligand="N-glycoloyl-alpha-neuraminate"
FT /ligand_id="ChEBI:CHEBI:176558"
FT /evidence="ECO:0000269|PubMed:18971931"
FT BINDING 59
FT /ligand="N-glycoloyl-alpha-neuraminate"
FT /ligand_id="ChEBI:CHEBI:176558"
FT /evidence="ECO:0000269|PubMed:18971931"
FT BINDING 101
FT /ligand="N-glycoloyl-alpha-neuraminate"
FT /ligand_id="ChEBI:CHEBI:176558"
FT /evidence="ECO:0000269|PubMed:18971931"
FT VARIANT 102
FT /note="K -> E (in strain: O29)"
FT /evidence="ECO:0000269|PubMed:17101670"
FT MUTAGEN 35
FT /note="S->A: Reduced toxicity of SubAB5 for Vero cells over
FT 99%, no longer binds to Vero cells, decreased binding to
FT human colon sections."
FT /evidence="ECO:0000269|PubMed:18971931"
FT MUTAGEN 38
FT /note="V->A: 50% toxicity of holotoxin on Vero cells,
FT SubAB5 complex about 60% less stable."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 59
FT /note="Q->A: Reduced toxicity of SubAB5 for Vero cells by
FT 87%."
FT /evidence="ECO:0000269|PubMed:18971931"
FT MUTAGEN 89
FT /note="Y->A: Decreased localization to host endoplasmic
FT reticulum lumen, nearly complete loss of toxicity of
FT holotoxin on Vero cells, SubAB5 complex about 60% less
FT stable."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 91
FT /note="Y->A: Holotoxin does not form."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 92
FT /note="T->D: Poor localization to host endoplasmic
FT reticulum lumen, nearly complete loss of toxicity of
FT holotoxin on Vero cells, too little SubAB5 complex forms to
FT test its stability."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 93
FT /note="T->A: No longer localizes to host endoplasmic
FT reticulum lumen, about 5% toxicity of holotoxin on Vero
FT cells, SubAB5 complex about 60% less stable."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 93
FT /note="T->D: Decreased localization to host endoplasmic
FT reticulum lumen, loss of toxicity of holotoxin on Vero
FT cells, SubAB5 complex about 50% less stable."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 94
FT /note="G->A: 50% toxicity of holotoxin on Vero cells, too
FT little SubAB5 complex forms to test its stability."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 94
FT /note="G->D: Holotoxin does not form."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 95
FT /note="Q->A: About 25% toxicity of holotoxin on Vero cells,
FT SubAB5 complex about 50% less stable."
FT /evidence="ECO:0000269|PubMed:23921389"
FT MUTAGEN 101
FT /note="Y->F: Reduced toxicity of SubAB5 for Vero cells by
FT 97%, greatly reduced binding to Vero cells, decreased
FT binding to human kidney sections."
FT /evidence="ECO:0000269|PubMed:18971931"
SQ SEQUENCE 141 AA; 15409 MW; C221950EC4A3992D CRC64;
MTIKRFFVCA GIMGCLSLNP AMAEWTGDAR DGMFSGVVIT QFHTGQIDNK PYFCIEGKQS
AGSSISACSM KNSSVWGASF STLYNQALYF YTTGQPVRIY YKPGVWTYPP FVKALTSNAL
VGLSTCTTST ECFGPDRKKN S
