tapasin

TAP binding protein (tapasin)
Available structures
PDB	Ortholog search: PDBe, RCSB
List of PDB id codes
	3F8U
Identifiers
Symbols	TAPBP; NGS17; TAPA; TPN; TPSN
External IDs	OMIM: 601962 MGI: 1201689 HomoloGene: 2401 GeneCards: TAPBP Gene
Gene Ontology
Molecular function	• protein binding; • peptide antigen-transporting ATPase activity; • MHC class I protein binding; • peptide antigen binding; • TAP1 binding; • TAP1 binding; • TAP2 binding; • TAP2 binding; • unfolded protein binding;
Cellular component	• Golgi membrane; • endoplasmic reticulum; • endoplasmic reticulum membrane; • microsome; • membrane; • integral to membrane; • phagocytic vesicle membrane; • MHC class I peptide loading complex; • TAP complex; • integral to lumenal side of endoplasmic reticulum membrane;
Biological process	• antigen processing and presentation of peptide antigen via MHC class I; • antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent; • protein complex assembly; • retrograde vesicle-mediated transport, Golgi to ER; • immune response; • antigen processing and presentation of endogenous peptide antigen via MHC class I; • antigen processing and presentation of exogenous peptide antigen via MHC class I; • peptide antigen stabilization;
	Sources: Amigo / QuickGO
RNA expression pattern
	More reference expression data
Orthologs
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タパシン TAPBP

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/04/06 03:37:03」(JST)

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TAP-associated glycoprotein also known as tapasin or TAPBP is a protein^[1]^[2] that in humans is encoded by the TAPBP gene.^[3]

Function

This gene encodes a transmembrane glycoprotein that mediates interaction between newly-assembled major histocompatibility complex (MHC) class I molecules and the transporter associated with antigen processing (TAP), which is required for the transport of antigenic peptides across the endoplasmic reticulum membrane. This interaction facilitates optimal peptide loading on the MHC class I molecule. Up to four complexes of MHC class I and tapasin may be bound to a single TAP molecule. Tapasin contains a C-terminal double-lysine motif (KKKAE) known to maintain membrane proteins in the endoplasmic reticulum. In humans, the tapasin gene lies within the major histocompatibility complex on chromosome 6. Alternative splicing results in three transcript variants encoding different isoforms.^[3]

Tapasin is a MHC class I antigen-processing molecule present in the lumen of the endoplasmic reticulum. It plays an important role in the maturation of MHC class I molecules in the ER lumen. Tapasin is one component of the peptide-loading complex, and can be found associated with MHC class I molecules after the MHC class I heavy chain has associated with Beta₂ microglobulin. The peptide-loading complex consists of TAP, tapasin, MHC class I, calreticulin, and ERp57. Tapasin recruits MHC class I molecules to the TAP peptide transporter, and also enhances loading of MHC class I with high-affinity peptides. Following loading of MHC class I with a high-affinity ligand, the interaction between tapasin and MHC class I disappears.^[4]

Interactions

Tapasin has been shown to interact with TAP1^[5]^[6] and HLA-A.^[6]

References

^ Sadasivan B, Lehner PJ, Ortmann B, Spies T, Cresswell P (August 1996). "Roles for calreticulin and a novel glycoprotein, tapasin, in the interaction of MHC class I molecules with TAP". Immunity 5 (2): 103–14. doi:10.1016/S1074-7613(00)80487-2. PMID 8769474.
^ Li S, Sjögren HO, Hellman U, Pettersson RF, Wang P (August 1997). "Cloning and functional characterization of a subunit of the transporter associated with antigen processing". Proc. Natl. Acad. Sci. U.S.A. 94 (16): 8708–13. doi:10.1073/pnas.94.16.8708. PMC 23091. PMID 9238042. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=23091.
^ ^a ^b "Entrez Gene: TAPBP TAP binding protein (tapasin)". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=6892.
^ Zhang Y, Williams DB (2006). "Assembly of MHC class I molecules within the endoplasmic reticulum". Immunol. Res. 35 (1–2): 151–62. doi:10.1385/IR:35:1:151. PMID 17003517.
^ Raghuraman, Gayatri; Lapinski Philip Edward, Raghavan Malini (Nov. 2002). "Tapasin interacts with the membrane-spanning domains of both TAP subunits and enhances the structural stability of TAP1 x TAP2 Complexes". J. Biol. Chem. (United States) 277 (44): 41786–94. doi:10.1074/jbc.M207128200. ISSN 0021-9258. PMID 12213826.
^ ^a ^b Paulsson, Kajsa M; Kleijmeer Monique J, Griffith Janice, Jevon Marc, Chen Shangwu, Anderson Per O, Sjogren Hans-Olov, Li Suling, Wang Ping (May. 2002). "Association of tapasin and COPI provides a mechanism for the retrograde transport of major histocompatibility complex (MHC) class I molecules from the Golgi complex to the endoplasmic reticulum". J. Biol. Chem. (United States) 277 (21): 18266–71. doi:10.1074/jbc.M201388200. ISSN 0021-9258. PMID 11884415.

External links

MeSH tapasin

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UpToDate Contents

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1. 免疫不全症を引き起こすCD3／T細胞受容体複合体疾患 cd3 t cell receptor complex disorders causing immunodeficiency
2. 抗原提示細胞 antigen presenting cells

English Journal

Expression of tapasin in rainbow trout tissues and cell lines and up regulation in a monocyte/macrophage cell line (RTS11) by a viral mimic and viral infection.

Sever L1, Vo NT1, Bols NC1, Dixon B2.Author information 1Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, Ontario N2L 3G1, Canada.2Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, Ontario N2L 3G1, Canada. Electronic address: bdixon@uwaterloo.ca.AbstractTapasin is a transmembrane glycoprotein that acts as a bridge between the transporter associated with antigen processing and the MHC class I receptor in mammals. Through the development of antibody against trout tapasin, this report demonstrates the detection of trout tapasin as a N-glycosylated 48kDa protein. Tissue and cell line distribution revealed that tapasin protein is expressed mainly in immune system organs and in rainbow trout epithelial cell lines from gill (RTgill-W1), liver (RTL-W1), and intestine (RTgutGC). An additional 20kDa band was observed in tissues and cell lines, and appeared to be most prominent in RTgutGC but was absent in peripheral blood leukocytes. Tapasin 48kDa protein was most strongly expressed in RTS11 (monocyte/macrophage cell line) and its regulation following dsRNA stimulation was explored. Upon poly I:C treatment and Chum Salmon Reovirus (CSV) infection, tapasin protein expression was upregulated up to 3.5 fold and 3 fold respectively, in parallel with increased expression of the glycosylated MH class I heavy chain, whereas the expression of the 20kDa form remained unchanged. Overall this work demonstrates the induction of tapasin protein by dsRNA stimulation, which implies its possible conserved regulation during viral infection in teleost cells.
Developmental and comparative immunology.Dev Comp Immunol.2013 Dec 7;44(1):86-93. doi: 10.1016/j.dci.2013.11.019. [Epub ahead of print]
Tapasin is a transmembrane glycoprotein that acts as a bridge between the transporter associated with antigen processing and the MHC class I receptor in mammals. Through the development of antibody against trout tapasin, this report demonstrates the detection of trout tapasin as a N-glycosylated 48k
PMID 24321527

The binding of TAPBPR and Tapasin to MHC class I is mutually exclusive.

Hermann C, Strittmatter LM, Deane JE, Boyle LH.Author information Department of Pathology, Cambridge Institute of Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom.AbstractThe loading of peptide Ags onto MHC class I molecules is a highly controlled process in which the MHC class I-dedicated chaperone tapasin is a key player. We recently identified a tapasin-related molecule, TAPBPR, as an additional component in the MHC class I Ag-presentation pathway. In this study, we show that the amino acid residues important for tapasin to interact with MHC class I are highly conserved on TAPBPR. We identify specific residues in the N-terminal and C-terminal domains of TAPBPR involved in associating with MHC class I. Furthermore, we demonstrate that residues on MHC class I crucial for its association with tapasin, such as T134, are also essential for its interaction with TAPBPR. Taken together, the data indicate that TAPBPR and tapasin bind in a similar orientation to the same face of MHC class I. In the absence of tapasin, the association of MHC class I with TAPBPR is increased. However, in the absence of TAPBPR, the interaction between MHC class I and tapasin does not increase. In light of our findings, previous data determining the function of tapasin in the MHC class I Ag-processing and presentation pathway must be re-evaluated.
Journal of immunology (Baltimore, Md. : 1950).J Immunol.2013 Dec 1;191(11):5743-50. doi: 10.4049/jimmunol.1300929. Epub 2013 Oct 25.
The loading of peptide Ags onto MHC class I molecules is a highly controlled process in which the MHC class I-dedicated chaperone tapasin is a key player. We recently identified a tapasin-related molecule, TAPBPR, as an additional component in the MHC class I Ag-presentation pathway. In this study,
PMID 24163410

A mechanistic basis for the co-evolution of chicken tapasin and major histocompatibility complex class I (MHC I) proteins.

van Hateren A, Carter R, Bailey A, Kontouli N, Williams AP, Kaufman J, Elliott T.Author information From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom.AbstractMHC class I molecules display peptides at the cell surface to cytotoxic T cells. The co-factor tapasin functions to ensure that MHC I becomes loaded with high affinity peptides. In most mammals, the tapasin gene appears to have little sequence diversity and few alleles and is located distal to several classical MHC I loci, so tapasin appears to function in a universal way to assist MHC I peptide loading. In contrast, the chicken tapasin gene is tightly linked to the single dominantly expressed MHC I locus and is highly polymorphic and moderately diverse in sequence. Therefore, tapasin-assisted loading of MHC I in chickens may occur in a haplotype-specific way, via the co-evolution of chicken tapasin and MHC I. Here we demonstrate a mechanistic basis for this co-evolution, revealing differences in the ability of two chicken MHC I alleles to bind and release peptides in the presence or absence of tapasin, where, as in mammals, efficient self-loading is negatively correlated with tapasin-assisted loading. We found that a polymorphic residue in the MHC I α3 domain thought to bind tapasin influenced both tapasin function and intrinsic peptide binding properties. Differences were also evident between the MHC alleles in their interactions with tapasin. Last, we show that a mismatched combination of tapasin and MHC alleles exhibit significantly impaired MHC I maturation in vivo and that polymorphic MHC residues thought to contact tapasin influence maturation efficiency. Collectively, this supports the possibility that tapasin and BF2 proteins have co-evolved, resulting in allele-specific peptide loading in vivo.
The Journal of biological chemistry.J Biol Chem.2013 Nov 8;288(45):32797-808. doi: 10.1074/jbc.M113.474031. Epub 2013 Sep 27.
MHC class I molecules display peptides at the cell surface to cytotoxic T cells. The co-factor tapasin functions to ensure that MHC I becomes loaded with high affinity peptides. In most mammals, the tapasin gene appears to have little sequence diversity and few alleles and is located distal to sever
PMID 24078633

Japanese Journal

Human cytomegalovirus inhibits tapasin-dependent peptide loading and optimization of the MHC class I peptide cargo for immune evasion

PARK B.
Immunity 20, 71, 2004
NAID 30010698272

The MHC-encoded class I molecule, H-2K^k, demonstrates distinct requirements of assembly factors for cell surface expression : roles of TAP, Tapasin and β_2-microglobulin