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PR01669

Identifier
TAPASIN  [View Relations]  [View Alignment]  
Accession
PR01669
No. of Motifs
8
Creation Date
25-JAN-2002
Title
Tapasin signature
Database References
Literature References
1. SULING, L., SJOGREN, H.O., HELMAN, U., PETTERSSON, R.F. AND WANG, P.
Cloning and functional characterization of a subunit of the transporter 
associated with antigen processing.
PROC.NATL.ACAD.SCI.U.S.A. 94 8708-8717 (1997).
 
2. ORTMANN, B., COPEMAN, J., LEHNER, P.J., SADASIVAN, B., HERBERG, J.A., 
GRANDEA, A.G., RIDDELL, S.R., TAMPE, R., SPIES, T., TROWSDALE, J. AND 
CRESSWELL, P.
A critical role for tapasin in the assembly and function of, multimeric MHC 
class I-TAP complexes.
SCIENCE 277 1306-1309 (1997).
 
3. SULING, L., PAULSSON, K.M., SJOGREN, H.O. AND WANG, P.
Peptide-bound major histocompatibility complex class I molecules associate 
with tapasin before dissociation form transporter associated with antigen 
processing.
J.BIOL.CHEM. 274 8649-8654 (1999).
 
4. BANGIA, N., LEHNER, P.J., HUGHES, E.A., SURMAN, M. AND CRESSWELL, P.
The N-terminal region of tapasin is required to stabilize the MHC class I 
loading complex. 
EUR.J.IMMUNOL. 29 1858-1870 (1999).
 
5. SULING, L., PAULSSON, K.M., CHEN, S., SJOGREN, H.O. AND WANG, P.
Tapasin is required for efficient peptide binding to transporter associated 
with antigen processing.
J.BIOL.CHEM. 275 1581-1586 (2000).

Documentation
Major histocompatibility complex (MHC) class I molecules present antigenic 
peptides to CD8 T cells. The majority of peptides found associated with 
class I molecules are derived from nuclear and cytosolic proteins, and they 
are generated largely by the proteasome complex. These peptides are 
transported from cytosol into the lumen of the endoplasmic reticulum  
(ER) by a peptide transporter, which is known as the transporter associated 
with antigen processing (TAP). TAP is a trimeric complex consisting of 
TAP1, TAP2 and tapasin (TAP-A). TAP1 and TAP2 are required for peptide 
transport. Tapasin, which actually serves as a docking site on the TAP 
complex specific for interaction with class I MHC molecules, is essential 
for peptide loading (up to four MHC class I-tapasin complexes have been
found to bind to each TAP molecule). However, since the exact mechanisms of
tapasin functions are still unknown, it has also been speculated that
tapasin may regulate the MHC class I release from the ER rather than 
directly loading peptides onto MHC class I molecules [1-4]. 
 
In studies of the interaction between MHC class I and TAP, it was found that 
TAP1, but not TAP2, is required for the association of TAP with class I 
molecules. Because tapasin is essential for the association of MHC class I 
to TAP, tapasin may directly interact with TAP1. Thus the predicted order of 
interaction between different molecules in the TAP complex is TAP2 to TAP1, 
TAP1 to tapasin, and tapasin to MHC class I molecules. Thus, by these linked 
events, the translocation and loading of peptides rapidly and efficiently
proceed in the same microenvironment [1,5].
 
Tapasin is a type I transmembrane (TM) glycoprotein with a double lysine
motif that is thought to be involved with mediating the retrieval of 
proteins back from the cis-Golgi, thus maintaining membrane proteins in the
ER [2]. It is encoded by an MHC-linked gene and is a member of the
immunoglobulin superfamily. Binding to TAP is mediated by the C-terminal
region, whereas its N-terminal 50 residues constitute the key element that
converts the MHC class I molecules and TAP weak interactions into a stable
complex [3,4].
 
Mouse tapasin shows 78% identity to the human tapasin, with identical signal 
peptide, N-glycosylation site, TM domain and double lysine motif at the
C-terminal end, indicative of similar functions for human and mouse tapasin.
An interesting feature of the sequence of mouse tapasin is the predicted
cytosolic domain, which shares less that 50% similarity with the human
proteins. In addition, mouse tapasin has 14 extra amino acid residues at 
the C-terminus, suggestive of species specificity of the tapasin function.
The cytosolic domain of tapasin may determine its interaction with MHC
class I or TAP1 [3].
 
TAPASIN is an 8-element fingerprint that provides a signature for the 
tapasins. The fingerprint was derived from an initial alignment of 4 
sequences: the motifs were drawn from conserved regions spanning virtually
the full alignment length - motifs 6 and 7 lie within the IG-like C1-type
domain. Two iterations on SPTR39_17f were required to reach convergence, at
which point a true set comprising 5 sequences was identified.
Summary Information
5 codes involving  8 elements
0 codes involving 7 elements
0 codes involving 6 elements
0 codes involving 5 elements
0 codes involving 4 elements
0 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
855555555
700000000
600000000
500000000
400000000
300000000
200000000
12345678
True Positives
Q99JC6        Q9D679        Q9HAN8        TPSN_HUMAN    
TPSN_MOUSE
Sequence Titles
Q99JC6      TAPASIN - Rattus norvegicus (Rat).            
Q9D679 TAP BINDING PROTEIN - Mus musculus (Mouse).
Q9HAN8 TAPASIN - Homo sapiens (Human).
TPSN_HUMAN TAPASIN PRECURSOR (TPSN) (TPN) (TAP-BINDING PROTEIN) (TAP-ASSOCIATED PROTEIN) (NGS-17) - Homo sapiens (Human).
TPSN_MOUSE TAPASIN PRECURSOR (TPSN) (TPN) (TAP-BINDING PROTEIN) (TAP-ASSOCIATED PROTEIN) - Mus musculus (Mouse).
Scan History
SPTR39_17f 2  100  NSINGLE    
Initial Motifs
Motif 1  width=9
Element Seqn Id St Int Rpt
PPPRPDLDP Q9D679 57 57 -
PPPRPDLDP TPSN_MOUSE 57 57 -
PPPRPDLDP Q99JC6 55 55 -
PPPRPDLDP TPSN_HUMAN 54 54 -

Motif 2 width=12
Element Seqn Id St Int Rpt
SLSSLLRPQPEP Q9D679 137 71 -
SLSSLLRPQPEP TPSN_MOUSE 137 71 -
SLSSLLRPLPEP Q99JC6 135 71 -
SLSSLLRPQPEP TPSN_HUMAN 134 71 -

Motif 3 width=18
Element Seqn Id St Int Rpt
GPPPFGLEWRRQHRGKGH Q9D679 201 52 -
GPPPFGLEWRRQHRGKGH TPSN_MOUSE 201 52 -
GPPPFGLEWRRQHRGKGH Q99JC6 199 52 -
GPPPFGLEWRRQHLGKGH TPSN_HUMAN 198 52 -

Motif 4 width=15
Element Seqn Id St Int Rpt
EPWGPWTGNGTFWLP Q9D679 248 29 -
EPWGPWTGNGTFWLP TPSN_MOUSE 248 29 -
DPWGPWTGNGTLWLP Q99JC6 247 30 -
EPWGPWTGNGTFWLP TPSN_HUMAN 245 29 -

Motif 5 width=17
Element Seqn Id St Int Rpt
YLATVHLPYLQGQVSLE Q9D679 272 9 -
YLATVHLPYLQGQVSLE TPSN_MOUSE 272 9 -
YLATVHLPYLQGQVSLE Q99JC6 271 9 -
YLATIHLPYLQGQVTLE TPSN_HUMAN 269 9 -

Motif 6 width=17
Element Seqn Id St Int Rpt
PGEAPPELLCLASHFFP Q9D679 309 20 -
PGEAPPELLCLASHFFP TPSN_MOUSE 309 20 -
PGEAPPELLCLVSHFYP Q99JC6 308 20 -
PGEAPPELLCLVSHFYP TPSN_HUMAN 306 20 -

Motif 7 width=20
Element Seqn Id St Int Rpt
WLSTIRHHSDGSVSQSGHLQ Q9D679 351 25 -
WLSTIRHHSDGSVSQSGHLQ TPSN_MOUSE 351 25 -
WVSTVRHHSDGSVSQSGHLQ Q99JC6 350 25 -
WLSALRHHSDGSVSLSGHLQ TPSN_HUMAN 348 25 -

Motif 8 width=25
Element Seqn Id St Int Rpt
SLPASGRSADVTLEVAGFSGPSIED Q9D679 391 20 -
SLPASGRSADVTLEVAGFSGPSIED TPSN_MOUSE 391 20 -
SLPSSGRSAEVTLEVAGFSGPSIED Q99JC6 390 20 -
SLPASGRSAEVTLEVAGLSGPSLED TPSN_HUMAN 388 20 -
Final Motifs
Motif 1  width=9
Element Seqn Id St Int Rpt
PPPRPDLDP Q9D679 57 57 -
PPPRPDLDP TPSN_MOUSE 57 57 -
PPPRPDLDP Q99JC6 55 55 -
PPPRPDLDP TPSN_HUMAN 54 54 -
PPPRPDLDP Q9HAN8 54 54 -

Motif 2 width=12
Element Seqn Id St Int Rpt
SLSSLLRPQPEP Q9D679 137 71 -
SLSSLLRPQPEP TPSN_MOUSE 137 71 -
SLSSLLRPLPEP Q99JC6 135 71 -
SLSSLLRPQPEP TPSN_HUMAN 134 71 -
SLSSLLRPQPEP Q9HAN8 134 71 -

Motif 3 width=18
Element Seqn Id St Int Rpt
GPPPFGLEWRRQHRGKGH Q9D679 201 52 -
GPPPFGLEWRRQHRGKGH TPSN_MOUSE 201 52 -
GPPPFGLEWRRQHRGKGH Q99JC6 199 52 -
GPPPFGLEWRRQHLGKGH TPSN_HUMAN 198 52 -
GPPPFGLEWRRQHLGKGH Q9HAN8 198 52 -

Motif 4 width=15
Element Seqn Id St Int Rpt
EPWGPWTGNGTFWLP Q9D679 248 29 -
EPWGPWTGNGTFWLP TPSN_MOUSE 248 29 -
DPWGPWTGNGTLWLP Q99JC6 247 30 -
EPWGPWTGNGTFWLP TPSN_HUMAN 245 29 -
EPWGPWTGNGTFWLP Q9HAN8 245 29 -

Motif 5 width=17
Element Seqn Id St Int Rpt
YLATVHLPYLQGQVSLE Q9D679 272 9 -
YLATVHLPYLQGQVSLE TPSN_MOUSE 272 9 -
YLATVHLPYLQGQVSLE Q99JC6 271 9 -
YLATIHLPYLQGQVTLE TPSN_HUMAN 269 9 -
YLATIHLPYLQGQVTLE Q9HAN8 269 9 -

Motif 6 width=17
Element Seqn Id St Int Rpt
PGEAPPELLCLASHFFP Q9D679 309 20 -
PGEAPPELLCLASHFFP TPSN_MOUSE 309 20 -
PGEAPPELLCLVSHFYP Q99JC6 308 20 -
PGEAPPELLCLVSHFYP TPSN_HUMAN 306 20 -
PGEAPPELLCLVSHFYP Q9HAN8 306 20 -

Motif 7 width=20
Element Seqn Id St Int Rpt
WLSTIRHHSDGSVSQSGHLQ Q9D679 351 25 -
WLSTIRHHSDGSVSQSGHLQ TPSN_MOUSE 351 25 -
WVSTVRHHSDGSVSQSGHLQ Q99JC6 350 25 -
WLSALRHHSDGSVSLSGHLQ TPSN_HUMAN 348 25 -
WLSALRHHSDGSVSLSGHLQ Q9HAN8 348 25 -

Motif 8 width=25
Element Seqn Id St Int Rpt
SLPASGRSADVTLEVAGFSGPSIED Q9D679 391 20 -
SLPASGRSADVTLEVAGFSGPSIED TPSN_MOUSE 391 20 -
SLPSSGRSAEVTLEVAGFSGPSIED Q99JC6 390 20 -
SLPASGRSAEVTLEVAGLSGPSLED TPSN_HUMAN 388 20 -
SLPASGRSAEVTLEVAGKSWELCGI Q9HAN8 388 20 -