کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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3346445 | 1215786 | 2008 | 5 صفحه PDF | دانلود رایگان |
The proteasome is the protein destroying machinery conserved in all eukaryotes and plays essential roles in various cellular processes. Apart from the conserved ‘standard’ proteasome, a special type of proteasome called ‘immunoproteasome’ exists in vertebrates for better presentation of antigenic peptides on MHC class I molecules. Recently, another vertebrate-specific proteasome was discovered in the thymus. This ‘thymoproteasome’ has a novel catalytic subunit ‘β5t’ with unusual enzymatic activity and is expressed exclusively in cortical thymic epithelial cells (cTECs), which catalyze positive selection of developing thymocytes. β5t-deficient mice exhibit severe impairment in CD8+ T cell development. These findings suggest that cTECs are quite unique cells capable of presenting a unique set of self-peptides that are not seen in other cells and are required for positive selection of CD8+ T cells.
Journal: Current Opinion in Immunology - Volume 20, Issue 2, April 2008, Pages 192–196