Generation of a functional, soluble tapasin protein from an alternatively spliced mRNA


Gao, B., Williams, A., Sewell, A. and Elliott, T. (2004) Generation of a functional, soluble tapasin protein from an alternatively spliced mRNA Genes and Immunity, 5, (2), pp. 101-108. (doi:10.1038/sj.gene.6364043). (PMID:14668790).

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Description/Abstract

The loading of newly synthesised MHC class I molecules (MHCI) with peptides requires the involvement of several endoplasmic reticulum (ER)-resident cofactors including calnexin, calreticulin, transporter associated with antigen processing, ERp57 and tapasin. In the absence of tapasin, MHC I complexes are loaded with suboptimal peptides and their recognition by cytotoxic T cells raised to high-affinity, immunodominant peptide epitopes is impaired. Here, we describe the cloning and functional assessment of an alternative spliced form of tapasin. From the EST database, we obtained a partially spliced tapasin cDNA that retained introns 4-6. When transfected into the tapasin-deficient cell line 0.220, the cDNA produced an alternatively spliced tapasin transcript that contained intron 5 (74 bp). This introduced a new stop codon that terminated translation immediately before the putative transmembrane domain and led to a tapasin molecule containing the lumenal domain plus 8 extra novel amino acids at its C-terminus. This molecule promoted peptide loading of HLA-B5 in 0.220 cell line, and restored normal HLA-B5 surface expression. However, the peptides loaded onto HLA-B5 were suboptimal compared to those loaded onto HLA-B5 in the presence of wild-type tapasin.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1038/sj.gene.6364043
ISSNs: 1466-4879 (print)
Keywords: tapasin, antigen processing, MHC class I assembly
Organisations: Cancer Sciences
ePrint ID: 384929
Date :
Date Event
March 2004Published
Date Deposited: 21 Jan 2016 11:32
Last Modified: 22 Feb 2017 07:14
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/384929

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