ID   P12I_HTL1C              Reviewed;          99 AA.
AC   P0CK16;
DT   31-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   31-MAY-2011, sequence version 1.
DT   23-FEB-2022, entry version 23.
DE   RecName: Full=Accessory protein p12I;
OS   Human T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Deltaretrovirus.
OX   NCBI_TaxID=11927;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2899128; DOI=10.1099/0022-1317-69-7-1695;
RA   Malik K.T.A., Even J., Karpas A.;
RT   "Molecular cloning and complete nucleotide sequence of an adult T cell
RT   leukaemia virus/human T cell leukaemia virus type I (ATLV/HTLV-I) isolate
RT   of Caribbean origin: relationship to other members of the ATLV/HTLV-I
RT   subgroup.";
RL   J. Gen. Virol. 69:1695-1710(1988).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA   Chappey C.;
RL   Submitted (NOV-1997) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: p12I is a modulator of T-lymphocyte proliferation and immune
CC       function and may contribute to establish a persistent infection. Binds
CC       and down-modulates cell surface expression of interleukin-2 receptors
CC       IL2RB and IL2RG. Also down-modulates cell surface MHC-I molecules by
CC       binding to free immature MHC-I heavy chains in the ER and targeting
CC       them to the proteasome for degradation. Binding to IL2RB mediates
CC       recruitment of JAK1 and JAK3. As a result of this interaction, p12I
CC       increases DNA-binding and transcriptional activity of STAT5 (By
CC       similarity). {ECO:0000250}.
CC   -!- SUBUNIT: p12I is a homodimer. Interacts with human CANX, CALR, ATP6V0C,
CC       IL2RB, IL2RG. Binds to MHC-I heavy chains HLA-A2, HLA-B7 and HLA-Cw4
CC       (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Host endoplasmic reticulum membrane
CC       {ECO:0000250}; Multi-pass membrane protein {ECO:0000250}. Host Golgi
CC       apparatus, host cis-Golgi network membrane {ECO:0000305}; Multi-pass
CC       membrane protein {ECO:0000305}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=p12I;
CC         IsoId=P0CK16-1; Sequence=Displayed;
CC       Name=p27I;
CC         IsoId=P0CK16-2; Sequence=VSP_041272;
CC   -!- PTM: Ubiquitinated; a fraction of P12I is degraded via the ubiquitin
CC       system. {ECO:0000250}.
CC   -!- MISCELLANEOUS: HTLV-1 lineages are divided in four clades, A
CC       (Cosmopolitan), B (Central African group), C (Melanesian group) and D
CC       (New Central African group).
CC   -!- SIMILARITY: Belongs to the HTLV-1 accessory protein p12I family.
CC       {ECO:0000305}.
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DR   EMBL; D13784; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; AF033817; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   PRIDE; P0CK16; -.
DR   Proteomes; UP000001061; Genome.
DR   Proteomes; UP000110593; Genome.
DR   GO; GO:0044167; C:host cell endoplasmic reticulum membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0044177; C:host cell Golgi apparatus; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0017124; F:SH3 domain binding; IEA:UniProtKB-KW.
DR   GO; GO:0046776; P:suppression by virus of host antigen processing and presentation of peptide antigen via MHC class I; IEA:UniProtKB-KW.
DR   InterPro; IPR021086; p12I.
DR   Pfam; PF12233; p12I; 1.
PE   3: Inferred from homology;
KW   Alternative splicing;
KW   Evasion of host immunity by viral interleukin-like protein;
KW   Host endoplasmic reticulum; Host Golgi apparatus; Host membrane;
KW   Host-virus interaction;
KW   Inhibition of host adaptive immune response by virus;
KW   Inhibition of host MHC class I molecule presentation by virus; Membrane;
KW   Reference proteome; SH3-binding; Transmembrane; Transmembrane helix;
KW   Ubl conjugation; Viral immunoevasion.
FT   CHAIN           1..99
FT                   /note="Accessory protein p12I"
FT                   /id="PRO_0000409221"
FT   TRANSMEM        12..32
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        48..68
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   MOTIF           4..11
FT                   /note="SH3-binding"
FT                   /evidence="ECO:0000255"
FT   MOTIF           33..38
FT                   /note="SH3-binding"
FT                   /evidence="ECO:0000255"
FT   MOTIF           70..77
FT                   /note="SH3-binding"
FT                   /evidence="ECO:0000255"
FT   MOTIF           88..93
FT                   /note="SH3-binding"
FT                   /evidence="ECO:0000255"
FT   VAR_SEQ         1
FT                   /note="M -> MPKTRRRPRRSQRKRPPTPWQPPPFSLQGLHLAFQLSSIAINPQLLH
FT                   FFFPST (in isoform p27I)"
FT                   /evidence="ECO:0000305"
FT                   /id="VSP_041272"
SQ   SEQUENCE   99 AA;  11128 MW;  FDCA1541C448FA78 CRC64;
     MLFRLLSPLS PLALTALLLF LLSPGEVSGL LLRPLPAPCL LLFLPFQILS NLLFLLFLPL
     FFSLPLLLSP SLPITMRFPA RWRFPPWRAP SQPAAAFLF