ID   PA_I77AD                Reviewed;         716 AA.
AC   P13177;
DT   01-JAN-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1990, sequence version 1.
DT   08-NOV-2023, entry version 95.
DE   RecName: Full=Polymerase acidic protein {ECO:0000255|HAMAP-Rule:MF_04063};
DE            EC=3.1.-.- {ECO:0000255|HAMAP-Rule:MF_04063};
DE   AltName: Full=RNA-directed RNA polymerase subunit P2 {ECO:0000255|HAMAP-Rule:MF_04063};
GN   Name=PA {ECO:0000255|HAMAP-Rule:MF_04063};
OS   Influenza A virus (strain A/Swine/Tennessee/26/1977 H1N1).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus;
OC   Alphainfluenzavirus influenzae; Influenza A virus.
OX   NCBI_TaxID=384479;
OH   NCBI_TaxID=8782; Aves.
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9823; Sus scrofa (Pig).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=2800339; DOI=10.1016/0042-6822(89)90202-x;
RA   Okazaki K., Kawaoka Y., Webster R.G.;
RT   "Evolutionary pathways of the PA genes of influenza A viruses.";
RL   Virology 172:601-608(1989).
CC   -!- FUNCTION: Plays an essential role in viral RNA transcription and
CC       replication by forming the heterotrimeric polymerase complex together
CC       with PB1 and PB2 subunits. The complex transcribes viral mRNAs by using
CC       a unique mechanism called cap-snatching. It consists in the hijacking
CC       and cleavage of host capped pre-mRNAs. These short capped RNAs are then
CC       used as primers for viral mRNAs. The PB2 subunit is responsible for the
CC       binding of the 5' cap of cellular pre-mRNAs which are subsequently
CC       cleaved after 10-13 nucleotides by the PA subunit that carries the
CC       endonuclease activity. {ECO:0000255|HAMAP-Rule:MF_04063}.
CC   -!- COFACTOR:
CC       Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_04063};
CC       Note=Binds 2 manganese ions per subunit. {ECO:0000255|HAMAP-
CC       Rule:MF_04063};
CC   -!- SUBUNIT: Influenza RNA polymerase is composed of three subunits: PB1,
CC       PB2 and PA. Interacts (via C-terminus) with PB1 (via N-terminus).
CC       {ECO:0000250|UniProtKB:P03433, ECO:0000255|HAMAP-Rule:MF_04063}.
CC   -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000255|HAMAP-Rule:MF_04063}.
CC       Host nucleus {ECO:0000255|HAMAP-Rule:MF_04063}. Note=PB1 and PA are
CC       transported in the host nucleus as a complex.
CC       {ECO:0000250|UniProtKB:P03433, ECO:0000255|HAMAP-Rule:MF_04063}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Ribosomal frameshifting; Named isoforms=2;
CC       Name=PA;
CC         IsoId=P13177-1; Sequence=Displayed;
CC       Name=PA-X;
CC         IsoId=P0DJV1-1; Sequence=External;
CC   -!- PTM: Phosphorylated on serines and threonines by host kinases,
CC       including human casein kinase II. {ECO:0000250|UniProtKB:P03433,
CC       ECO:0000255|HAMAP-Rule:MF_04063}.
CC   -!- SIMILARITY: Belongs to the influenza viruses PA family.
CC       {ECO:0000255|HAMAP-Rule:MF_04063}.
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DR   EMBL; M26077; AAA43681.1; -; Genomic_RNA.
DR   SMR; P13177; -.
DR   MEROPS; S62.001; -.
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:0004519; F:endonuclease activity; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0075526; P:cap snatching; IEA:UniProtKB-UniRule.
DR   GO; GO:0006351; P:DNA-templated transcription; IEA:UniProtKB-UniRule.
DR   GO; GO:0039523; P:suppression by virus of host mRNA transcription via inhibition of RNA polymerase II activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0039694; P:viral RNA genome replication; IEA:InterPro.
DR   Gene3D; 3.40.91.90; Influenza RNA-dependent RNA polymerase subunit PA, endonuclease domain; 1.
DR   HAMAP; MF_04063; INFV_PA; 1.
DR   InterPro; IPR037534; INFV_PA.
DR   InterPro; IPR001009; PA/PA-X.
DR   InterPro; IPR038372; PA/PA-X_sf.
DR   Pfam; PF00603; Flu_PA; 1.
PE   3: Inferred from homology;
KW   Cap snatching; Endonuclease;
KW   Eukaryotic host gene expression shutoff by virus;
KW   Eukaryotic host transcription shutoff by virus; Host cytoplasm;
KW   Host gene expression shutoff by virus; Host nucleus;
KW   Host-virus interaction; Hydrolase;
KW   Inhibition of host RNA polymerase II by virus; Manganese; Metal-binding;
KW   Nuclease; Phosphoprotein; Ribosomal frameshifting.
FT   CHAIN           1..716
FT                   /note="Polymerase acidic protein"
FT                   /id="PRO_0000078805"
FT   MOTIF           124..139
FT                   /note="Nuclear localization signal 1 (NLS1)"
FT                   /evidence="ECO:0000250|UniProtKB:P03433, ECO:0000255|HAMAP-
FT                   Rule:MF_04063"
FT   MOTIF           184..247
FT                   /note="Nuclear localization signal 2 (NLS2)"
FT                   /evidence="ECO:0000250|UniProtKB:P03433, ECO:0000255|HAMAP-
FT                   Rule:MF_04063"
FT   BINDING         41
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04063"
FT   BINDING         80
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04063"
FT   BINDING         108
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04063"
FT   BINDING         108
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04063"
FT   BINDING         120
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04063"
SQ   SEQUENCE   716 AA;  82873 MW;  D808F729BCF5848A CRC64;
     MEDFVRQCFN PMIVELAEKT MKEYGENPKI ETNKFAAICT HMEVCFMYSD FHFINERGES
     IIIEPGDSNA LLKHRFEIIE GRDRNMAWTV VNSICNTTGV GKPRFLPDLY DYKEDRFIKI
     GVTRREVHIY YLEKANKIKS EETHIHIFSF TGEEMATKAD YTLDEESRAR IKTRLFTIRQ
     EMASRGLWDS FRQSERGEET IEERFEIKGT MRRLADQSLP PNFSSFDNFR AYVDGFEPNG
     YIEGKLSQMS REVNARIEPF LKTTPRPLRL PCGPPCFQRS KFLLMDALKL SIEDPSHEGE
     GIPLYDAVRC MKTFFGWKEP IIVKPHEKGI NSNYLLAWKQ VLAEIQDFED EKKIPRVKNM
     KKTSPLKWAL GENMAPEKVD FEDCKDVSDL KQYDGDEPEF RSLASWIQNE FNKACELTDS
     SWLEIDEIGE DIAPLEHIAS MRRNYFTAEV SHCRATEYIM KGVYINTALL NASCAAMDDF
     QLIPMISKCR TKEGRRKTNL YGFIIKGRSH LRNDTDVVNF VSMEFSLTDP RLELHKWEKY
     SILEIGDMVL RTAIGQVARP MFLYVRTNGT SKIKMKWGME MRRCLLQSLQ QIESMIEAES
     SVKEKDMTKE FFENKSETWP IGESPKGVEE GSIGKVCRTL LAKSVFNCLY ASPQLEGFSA
     ESRKLLLIVQ ALRDNLEPGT FDLGGLYESI EECLINDPWV LLNASWFNSF LTHALR
//