Immunoproteasoomi

Immunoproteasome is a specialized form of the proteasome found in immune cells. The proteasome is a large protein complex within cells that functions as a cellular recycling center, breaking down unneeded or damaged proteins. The immunoproteasome is a variant of the standard or constitutive proteasome, meaning it has a slightly different composition and function.

Its primary role is to generate peptides that are presented on the cell surface by MHC class I molecules. These presented peptides are crucial for the adaptive immune system, as they signal to T cells whether a cell is healthy or infected by a pathogen, or if it is cancerous. The immunoproteasome is particularly important in generating peptides that are efficiently recognized by T cells, thus playing a critical role in initiating and shaping immune responses.

The immunoproteasome differs from the constitutive proteasome by having three inducible catalytic subunits (LMP2, LMP7, and MECL-1) that replace some of the subunits found in the standard proteasome. This subunit composition alters the cleavage specificity of the immunoproteasome, leading to the production of peptides that are more immunogenic. Its expression is upregulated in immune cells, especially in response to inflammatory signals like interferons. This highlights its specific involvement in immune surveillance and T cell-mediated immunity.