ID   NS1_INBAC               Reviewed;         281 AA.
AC   P69253; P13883;
DT   01-MAR-2005, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2005, sequence version 1.
DT   23-FEB-2022, entry version 48.
DE   RecName: Full=Non-structural protein 1 {ECO:0000255|HAMAP-Rule:MF_04066};
DE            Short=NS1 {ECO:0000255|HAMAP-Rule:MF_04066};
DE   AltName: Full=NS1A {ECO:0000255|HAMAP-Rule:MF_04066};
GN   Name=NS {ECO:0000255|HAMAP-Rule:MF_04066};
OS   Influenza B virus (strain B/Ann Arbor/1/1966 [cold-adapted]).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Betainfluenzavirus.
OX   NCBI_TaxID=11522;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=3354202; DOI=10.1016/0042-6822(88)90284-x;
RA   Deborde D.C., Donabedian A.M., Herlocher M.L., Naeve C.W., Maassab H.F.;
RT   "Sequence comparison of wild-type and cold-adapted B/Ann Arbor/1/66
RT   influenza virus genes.";
RL   Virology 163:429-443(1988).
RN   [2]
RP   REVIEW.
RX   PubMed=12758165; DOI=10.1016/s0042-6822(03)00119-3;
RA   Krug R.M., Yuan W., Noah D.L., Latham A.G.;
RT   "Intracellular warfare between human influenza viruses and human cells: the
RT   roles of the viral NS1 protein.";
RL   Virology 309:181-189(2003).
CC   -!- FUNCTION: Binds and inhibits the conjugation of the ubiquitin-like
CC       G1P2/ISG15 protein to its target proteins. Since G1P2/ISG15 is an early
CC       antiviral protein, NS1 may inhibit the host antiviral response.
CC       Prevents EIF2AK2/PKR activation, either by binding double strand RNA or
CC       by interacting directly with EIF2AK2/PKR. Also binds poly(A) and U6
CC       snRNA. {ECO:0000255|HAMAP-Rule:MF_04066}.
CC   -!- SUBUNIT: Homodimer. Interacts with and inhibits human G1P2 conjugation
CC       by UBE1L. {ECO:0000255|HAMAP-Rule:MF_04066}.
CC   -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000255|HAMAP-Rule:MF_04066}.
CC       Host nucleus {ECO:0000255|HAMAP-Rule:MF_04066}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=NS1;
CC         IsoId=P69253-1; Sequence=Displayed;
CC       Name=NEP; Synonyms=NS2;
CC         IsoId=P69253-2; Sequence=Not described;
CC   -!- SIMILARITY: Belongs to the influenza B viruses NS1 family.
CC       {ECO:0000255|HAMAP-Rule:MF_04066}.
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DR   EMBL; M20224; AAA43754.1; -; Genomic_RNA.
DR   SMR; P69253; -.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0030291; F:protein serine/threonine kinase inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0039579; P:suppression by virus of host ISG15-protein conjugation; IEA:UniProtKB-KW.
DR   GO; GO:0039580; P:suppression by virus of host PKR signaling; IEA:UniProtKB-KW.
DR   GO; GO:0039502; P:suppression by virus of host type I interferon-mediated signaling pathway; IEA:UniProtKB-KW.
DR   HAMAP; MF_04066; INFV_NS1; 1.
DR   InterPro; IPR004208; NS1.
DR   InterPro; IPR009068; S15_NS1_RNA-bd.
DR   Pfam; PF02942; Flu_B_NS1; 1.
DR   PIRSF; PIRSF003938; Flu_B_NS1; 1.
DR   SUPFAM; SSF47060; SSF47060; 1.
PE   3: Inferred from homology;
KW   Alternative splicing; Host cytoplasm; Host nucleus; Host-virus interaction;
KW   Inhibition of host innate immune response by virus;
KW   Inhibition of host interferon signaling pathway by virus;
KW   Inhibition of host ISG15 by virus; Inhibition of host PKR by virus;
KW   Interferon antiviral system evasion; RNA-binding; Viral immunoevasion.
FT   CHAIN           1..281
FT                   /note="Non-structural protein 1"
FT                   /id="PRO_0000078957"
FT   REGION          1..103
FT                   /note="G1P2-binding"
FT   REGION          1..93
FT                   /note="RNA-binding and homodimerization"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04066"
FT   MOTIF           50..55
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04066"
SQ   SEQUENCE   281 AA;  31854 MW;  2A87DC904AB70649 CRC64;
     MADNMTTTQI EVGPGATNAT INFEAGILEC YERLSSQRAL DYPGQDRLNR LKRKLESRIK
     THNKSEPESK RMSLEERKAI GVKMMKVLLF MNPSAGIEGF EPYCMKNSSN SNCPNCNWTD
     YPPTPGKCLD DIEEEPENVD DPTEIVLRDM NNKDARQKIK EEVNTQKEGK FRLTIKRDIR
     NVLSLRVLVN GTFLKHPNGY KSLSTLHRLN AYDQSGRLVA KLVATDDLTV EDEEDGHRIL
     NSLFERFNEG HSKPIRAAET AVGVLSQFGQ EHRLSPEEGD N