ID   SOCB_CAUVN              Reviewed;         237 AA.
AC   A0A0H3CC30;
DT   30-AUG-2017, integrated into UniProtKB/Swiss-Prot.
DT   16-SEP-2015, sequence version 1.
DT   25-MAY-2022, entry version 18.
DE   RecName: Full=DNA replication inhibitor toxin SocB {ECO:0000303|PubMed:24239291};
GN   Name=socB {ECO:0000303|PubMed:24239291}; OrderedLocusNames=CCNA_03629;
OS   Caulobacter vibrioides (strain NA1000 / CB15N) (Caulobacter crescentus).
OC   Bacteria; Proteobacteria; Alphaproteobacteria; Caulobacterales;
OC   Caulobacteraceae; Caulobacter.
OX   NCBI_TaxID=565050;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=NA1000 / CB15N;
RX   PubMed=20472802; DOI=10.1128/jb.00255-10;
RA   Marks M.E., Castro-Rojas C.M., Teiling C., Du L., Kapatral V.,
RA   Walunas T.L., Crosson S.;
RT   "The genetic basis of laboratory adaptation in Caulobacter crescentus.";
RL   J. Bacteriol. 192:3678-3688(2010).
RN   [2]
RP   FUNCTION AS A TOXIN, INTERACTION WITH SOCA AND DNAN, SUBCELLULAR LOCATION,
RP   INDUCTION, DEGRADATION, DISRUPTION PHENOTYPE, AND MUTAGENESIS OF GLN-52.
RX   PubMed=24239291; DOI=10.1016/j.molcel.2013.10.014;
RA   Aakre C.D., Phung T.N., Huang D., Laub M.T.;
RT   "A bacterial toxin inhibits DNA replication elongation through a direct
RT   interaction with the beta sliding clamp.";
RL   Mol. Cell 52:617-628(2013).
CC   -!- FUNCTION: Toxic component of an atypical type II toxin-antitoxin (TA)
CC       system. Upon overexpression in the absence of its cognate antitoxin
CC       SocA, leads to inhibition of colony formation, cellular filamentation,
CC       incomplete DNA replication and induction of the SOS response. Exercises
CC       toxicity by binding the beta sliding clamp (dnaN), blocking DNA
CC       replication and leading to premature replication fork collapse and
CC       incomplete cell division. Unlike most type II TA systems, the SocB
CC       toxin is unstable and targeted by its cognate antitoxin SocA for
CC       degradation by ClpXP. Not toxic upon expression in E.coli.
CC       {ECO:0000269|PubMed:24239291}.
CC   -!- SUBUNIT: Interacts with cognate antitoxin SocA and with beta sliding
CC       clamp (dnaN). {ECO:0000269|PubMed:24239291}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000305|PubMed:24239291}. Note=A
CC       tagged overexpressed form of SocB forms a discrete locus during DNA
CC       replication which co-localizes with beta sliding clamps (dnaN), but the
CC       locus disperses early. Loci formation depends on DnaA, the replication
CC       initiator protein (PubMed:24239291). {ECO:0000269|PubMed:24239291}.
CC   -!- INDUCTION: Induced by DNA damaging agent mitomycin C, part of the socA-
CC       socB operon. {ECO:0000269|PubMed:24239291}.
CC   -!- PTM: Degraded by ClpXP, recognition of SocB by ClpX requires SocA.
CC       {ECO:0000269|PubMed:24239291}.
CC   -!- DISRUPTION PHENOTYPE: Deletion of this gene allows growth of cells
CC       disrupted for clpP or clpX, deletions which are otherwise lethal.
CC       {ECO:0000269|PubMed:24239291}.
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DR   EMBL; CP001340; ACL97094.1; -; Genomic_DNA.
DR   RefSeq; WP_015923298.1; NC_011916.1.
DR   RefSeq; YP_002519002.1; NC_011916.1.
DR   AlphaFoldDB; A0A0H3CC30; -.
DR   EnsemblBacteria; ACL97094; ACL97094; CCNA_03629.
DR   GeneID; 7329714; -.
DR   KEGG; ccs:CCNA_03629; -.
DR   PATRIC; fig|565050.3.peg.3543; -.
DR   HOGENOM; CLU_079290_0_0_5; -.
DR   OMA; MARETYS; -.
DR   OrthoDB; 1306423at2; -.
DR   Proteomes; UP000001364; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
PE   1: Evidence at protein level;
KW   Cytoplasm; Reference proteome; Toxin-antitoxin system.
FT   CHAIN           1..237
FT                   /note="DNA replication inhibitor toxin SocB"
FT                   /id="PRO_0000441113"
FT   MUTAGEN         52
FT                   /note="Q->A: Tagged overexpressed SocB is not longer toxic,
FT                   no longer makes foci during DNA replication and no longer
FT                   interacts with beta sliding clamp (dnaA). Protein still
FT                   interacts with SocA."
FT                   /evidence="ECO:0000269|PubMed:24239291"
SQ   SEQUENCE   237 AA;  27111 MW;  9CA84D6F50CD1E43 CRC64;
     MKKHRLPDTE LARIAPLAPD ARRKALLKFK NGFPDFSYEP TRRRLPELTN AQPSLLSLGD
     TEWSKIESGL KRLKNEKEAA SNIEVAELLY NFIREEKYIA VMEPFGKLQL GAGVAISYWS
     DAIFFGPDGP TIFGFDFRRA GGFNDSARRF AFSAQHEHIR QRGDDYATAK LGLVQFPALR
     NGTRKVRVEF ADQVELIPYD ELIQMARETY SVWFEILEQR EDEARKTGTG GSWWDGD