ID   RPC3_LAMBD              Reviewed;          54 AA.
AC   P03044;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   07-APR-2021, entry version 89.
DE   RecName: Full=Protease inhibitor III;
GN   Name=cIII; OrderedLocusNames=lambdap86;
OS   Escherichia phage lambda (Bacteriophage lambda).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Siphoviridae; Lambdavirus.
OX   NCBI_TaxID=10710;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=6221115; DOI=10.1016/0022-2836(82)90546-0;
RA   Sanger F., Coulson A.R., Hong G.F., Hill D.F., Petersen G.B.;
RT   "Nucleotide sequence of bacteriophage lambda DNA.";
RL   J. Mol. Biol. 162:729-773(1982).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=6458018; DOI=10.1093/nar/9.18.4639;
RA   Ineichen K., Shepherd J.C.W., Bickle T.A.;
RT   "The DNA sequence of the phage lambda genome between PL and the gene bet.";
RL   Nucleic Acids Res. 9:4639-4653(1981).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [MRNA] OF 1-17.
RX   PubMed=2957696; DOI=10.1073/pnas.84.18.6511;
RA   Altuvia S., Locker-Giladi H., Koby S., Ben-Nun O., Oppenheim A.B.;
RT   "RNase III stimulates the translation of the cIII gene of bacteriophage
RT   lambda.";
RL   Proc. Natl. Acad. Sci. U.S.A. 84:6511-6515(1987).
RN   [4]
RP   MUTAGENESIS.
RX   PubMed=1828895; DOI=10.1073/pnas.88.12.5217;
RA   Kornitzer D., Altuvia S., Oppenheim A.B.;
RT   "The activity of the CIII regulator of lambdoid bacteriophages resides
RT   within a 24-amino acid protein domain.";
RL   Proc. Natl. Acad. Sci. U.S.A. 88:5217-5221(1991).
RN   [5]
RP   FUNCTION.
RX   PubMed=8990286; DOI=10.1128/jb.179.2.358-363.1997;
RA   Herman C., Thevenet D., D'Ari R., Bouloc P.;
RT   "The HflB protease of Escherichia coli degrades its inhibitor lambda
RT   cIII.";
RL   J. Bacteriol. 179:358-363(1997).
RN   [6]
RP   FUNCTION.
RX   PubMed=17426811; DOI=10.1371/journal.pone.0000363;
RA   Kobiler O., Rokney A., Oppenheim A.B.;
RT   "Phage lambda CIII: a protease inhibitor regulating the lysis-lysogeny
RT   decision.";
RL   PLoS ONE 2:E363-E363(2007).
RN   [7]
RP   FUNCTION.
RX   PubMed=18721134; DOI=10.1111/j.1742-4658.2008.06610.x;
RA   Halder S., Banerjee S., Parrack P.;
RT   "Direct CIII-HflB interaction is responsible for the inhibition of the HflB
RT   (FtsH)-mediated proteolysis of Escherichia coli sigma(32) by lambdaCIII.";
RL   FEBS J. 275:4767-4772(2008).
CC   -!- FUNCTION: Acts as a host protease inhibitor that allows the virus to
CC       initiate latency. Following infection, prevents protein cII degradation
CC       by inhibiting host protease FtsH (cII is a factor that initiates the
CC       expression of repressor cI, the major component promoting latency).
CC       Functions as a competitive inhibitor (and thus as alternative
CC       substrate) of host FtsH and thereby prevents binding of cII substrate.
CC       In turn, stabilization of cII transcriptional activator allows protein
CC       cI expression and thus initiation of latency.
CC       {ECO:0000269|PubMed:17426811, ECO:0000269|PubMed:18721134,
CC       ECO:0000269|PubMed:8990286}.
CC   -!- SIMILARITY: Belongs to the lambda phage cIII protein family.
CC       {ECO:0000305}.
CC   -!- CAUTION: PubMed:6458018 assigned the gene cIII product to the sequence
CC       of the kil gene protein. {ECO:0000305}.
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DR   EMBL; J02459; AAA96573.1; -; Genomic_DNA.
DR   EMBL; M17427; AAA32244.1; -; mRNA.
DR   PIR; C94614; QCBP3L.
DR   RefSeq; NP_040620.1; NC_001416.1.
DR   SMR; P03044; -.
DR   MEROPS; I75.001; -.
DR   GeneID; 2703471; -.
DR   GeneID; 2703542; -.
DR   KEGG; vg:3827056; -.
DR   Proteomes; UP000001711; Genome.
DR   GO; GO:0019042; P:viral latency; IEA:UniProtKB-KW.
DR   InterPro; IPR013056; Phage_lambda_CIII.
DR   Pfam; PF02061; Lambda_CIII; 1.
DR   PRINTS; PR00936; BPLRPCIII.
DR   PROSITE; PS00553; LAMBDA_PHAGE_CIII; 1.
PE   1: Evidence at protein level;
KW   Activator; Reference proteome; Viral latency;
KW   Viral latency initiation and maintenance.
FT   CHAIN           1..54
FT                   /note="Protease inhibitor III"
FT                   /id="PRO_0000077595"
FT   MUTAGEN         21
FT                   /note="R->P: Low cIII activity."
FT                   /evidence="ECO:0000269|PubMed:1828895"
SQ   SEQUENCE   54 AA;  6047 MW;  35AB2E100460C198 CRC64;
     MQYAIAGWPV AGCPSESLLE RITRKLRDGW KRLIDILNQP GVPKNGSNTY GYPD