UniProt functional annotation for P36370



	UniProt functional annotation for P36370

UniProt code: P36370.

Organism: Rattus norvegicus (Rat).

Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae; Murinae; Rattus.

Function: ABC transporter associated with antigen processing (PubMed:17018292). In complex with TAP2 mediates unidirectional translocation of peptide antigens from cytosol to endoplasmic reticulum (ER) for loading onto MHC class I (MHCI) molecules (By similarity). Uses the chemical energy of ATP to export peptides against the concentration gradient (By similarity). During the transport cycle alternates between 'inward-facing' state with peptide binding site facing the cytosol to 'outward-facing' state with peptide binding site facing the ER lumen. Peptide antigen binding to ATP-loaded TAP1-TAP2 induces a switch to hydrolysis-competent 'outward-facing' conformation ready for peptide loading onto nascent MHCI molecules. Subsequently ATP hydrolysis resets the transporter to the 'inward facing' state for a new cycle (By similarity). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (By similarity). {ECO:0000250|UniProtKB:Q03518, ECO:0000269|PubMed:17018292}.

Catalytic activity: Reaction=a peptide antigen(in) + ATP + H2O = a peptide antigen(out) + ADP + H(+) + phosphate; Xref=Rhea:RHEA:65972, Rhea:RHEA-COMP:16941, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:166823, ChEBI:CHEBI:456216; Evidence={ECO:0000305|PubMed:17018292}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:65973; Evidence={ECO:0000305|PubMed:17018292};

Cofactor: Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000269|PubMed:17018292, ECO:0000269|PubMed:25377891};

Subunit: Heterodimer of TAP1 and TAP2 (TAP1-TAP2). A component of the peptide loading complex (PLC), interacts via TAPBP with MHCI heterodimer; this interaction mediates peptide-MHCI assembly. Interacts with PSMB5 and PSMB8. {ECO:0000250|UniProtKB:Q03518}.

Subcellular location: Endoplasmic reticulum membrane {ECO:0000250|UniProtKB:Q03518}; Multi-pass membrane protein {ECO:0000255}. Note=The transmembrane segments seem to form a pore in the membrane.

Domain: The peptide-binding site is shared between the cytoplasmic loops of TAP1 and TAP2. {ECO:0000250|UniProtKB:Q03518}.

Domain: The nucleotide-binding domain (NBD) mediates ATP hydrolysis coupled to peptide translocation. Two ATP molecules are accommodated at distinct nucleotide binding sites (NBS) at TAP1-TAP2 dimer interface. Each NBS is formed by Walker A (GxxGxGKST) and Q-loop motifs from NBD of one subunit, while the NBD from the second subunit completes the active site by contributing the C loop motif (LSGGQ). Each ATP molecule is coordinated via the beta- and gamma-phosphates to a Mg2+ ion, which is necessary for ATP hydrolysis. {ECO:0000269|PubMed:17018292}.

Similarity: Belongs to the ABC transporter superfamily. ABCB family. MHC peptide exporter (TC 3.A.1.209) subfamily. {ECO:0000305}.

Sequence caution: Sequence=CAA40742.1; Type=Erroneous initiation; Evidence={ECO:0000305};

Annotations taken from UniProtKB at the EBI.


Organism:		Rattus norvegicus (Rat).
Taxonomy:		Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae; Murinae; Rattus.



Function:		ABC transporter associated with antigen processing (PubMed:17018292). In complex with TAP2 mediates unidirectional translocation of peptide antigens from cytosol to endoplasmic reticulum (ER) for loading onto MHC class I (MHCI) molecules (By similarity). Uses the chemical energy of ATP to export peptides against the concentration gradient (By similarity). During the transport cycle alternates between 'inward-facing' state with peptide binding site facing the cytosol to 'outward-facing' state with peptide binding site facing the ER lumen. Peptide antigen binding to ATP-loaded TAP1-TAP2 induces a switch to hydrolysis-competent 'outward-facing' conformation ready for peptide loading onto nascent MHCI molecules. Subsequently ATP hydrolysis resets the transporter to the 'inward facing' state for a new cycle (By similarity). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (By similarity). {ECO:0000250\|UniProtKB:Q03518, ECO:0000269\|PubMed:17018292}.


Catalytic activity:		Reaction=a peptide antigen(in) + ATP + H2O = a peptide antigen(out) + ADP + H(+) + phosphate; Xref=Rhea:RHEA:65972, Rhea:RHEA-COMP:16941, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:166823, ChEBI:CHEBI:456216; Evidence={ECO:0000305\|PubMed:17018292}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:65973; Evidence={ECO:0000305\|PubMed:17018292};
Cofactor:		Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000269\|PubMed:17018292, ECO:0000269\|PubMed:25377891};
Subunit:		Heterodimer of TAP1 and TAP2 (TAP1-TAP2). A component of the peptide loading complex (PLC), interacts via TAPBP with MHCI heterodimer; this interaction mediates peptide-MHCI assembly. Interacts with PSMB5 and PSMB8. {ECO:0000250\|UniProtKB:Q03518}.
Subcellular location:		Endoplasmic reticulum membrane {ECO:0000250\|UniProtKB:Q03518}; Multi-pass membrane protein {ECO:0000255}. Note=The transmembrane segments seem to form a pore in the membrane.
Domain:		The peptide-binding site is shared between the cytoplasmic loops of TAP1 and TAP2. {ECO:0000250\|UniProtKB:Q03518}.
Domain:		The nucleotide-binding domain (NBD) mediates ATP hydrolysis coupled to peptide translocation. Two ATP molecules are accommodated at distinct nucleotide binding sites (NBS) at TAP1-TAP2 dimer interface. Each NBS is formed by Walker A (GxxGxGKST) and Q-loop motifs from NBD of one subunit, while the NBD from the second subunit completes the active site by contributing the C loop motif (LSGGQ). Each ATP molecule is coordinated via the beta- and gamma-phosphates to a Mg2+ ion, which is necessary for ATP hydrolysis. {ECO:0000269\|PubMed:17018292}.
Similarity:		Belongs to the ABC transporter superfamily. ABCB family. MHC peptide exporter (TC 3.A.1.209) subfamily. {ECO:0000305}.
Sequence caution:		Sequence=CAA40742.1; Type=Erroneous initiation; Evidence={ECO:0000305};