Resumo

ZELADA VALDES, Adrian. The proteasome: subtypes and involvement in central tolerance. Rev Cubana Invest Bioméd [online]. 2019, vol.38, n.2, pp.254-276.  Epub 18-Jun-2019. ISSN 0864-0300.

The proteasome is a large protein complex mainly located in all eukaryote cells, where it plays a very important role in cellular processes like differentiation, cycle progression, development and apoptosis. There are several types of proteasomes: constitutive, intermediate, immunoproteasome and thymoproteasome, which are present in cells depending on their structure and functions. However, they are found in cells of the immune system, where they play a very important role not only in antigenic processes related to the immune response, but also in central tolerance mechanisms during T lymphocyte ontogeny in the thymus. Thymic cortical epithelial cells are therefore antigen-presenting cells with unique intrinsic characteristics, since they contain thymoproteasome, cathepsin L, and thymus-specific serine protease. Additionally, a high rate of macroautophagy has been observed in comparison with bibr cells of the body. They are thus essential to obtain a repertoire of CD4+ and CD8+ T lymphocytes capable of distinguishing the body's own elements from alien structures. Therefore, central tolerance should not be viewed as only defined by the negative selection mechanism, since positive selection also plays a very important role in defining the repertoire of non-autoreactive T lymphocyte clones. The purpose of the study was to discuss the proteasome, the types of proteasomes and their involvement in T lymphocyte central tolerance.

Palavras-chave : ubiquitin; proteasome; immunoproteasome; thymoproteasome; positive selection; central tolerance.

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