antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-dependent

Definition

Target type: biologicalprocess

The process in which an antigen-presenting cell expresses a peptide antigen of endogenous origin on its cell surface in association with an MHC class I protein complex following intracellular transport via a TAP-dependent ER pathway. The peptide is typically a fragment of a larger endogenous protein which has been degraded within the cell and becomes associated with the MHC class I molecule in the ER following TAP-dependent transport from the cytosol. Class I here refers to classical class I molecules. [GOC:add, ISBN:0781735149, PMID:14647477, PMID:15771591]

The process of antigen processing and presentation of endogenous peptide antigen via MHC class I via the ER pathway, TAP-dependent, begins with the generation of peptide fragments from proteins synthesized within the cell. These proteins are targeted to the endoplasmic reticulum (ER), where they are degraded by the proteasome, a large protein complex responsible for protein degradation. The proteasome generates short peptides, typically 8-10 amino acids in length. These peptides are then transported into the ER lumen by the transporter associated with antigen processing (TAP). TAP is a heterodimer composed of two subunits, TAP1 and TAP2, and acts as a pump powered by ATP hydrolysis. The TAP transporter displays specificity for peptides with a certain length and amino acid composition. Once in the ER lumen, the peptides associate with major histocompatibility complex (MHC) class I molecules. MHC class I molecules are heterodimers composed of a heavy chain and a light chain called beta-2 microglobulin. The heavy chain contains a peptide binding groove that can accommodate the peptide fragments. The association between the peptide and MHC class I molecule occurs in the ER, where the two molecules assemble into a stable complex. The peptide-loaded MHC class I molecules then exit the ER and are transported through the Golgi apparatus to the cell surface. The peptide-MHC class I complexes are then displayed on the cell surface, where they can be recognized by cytotoxic T lymphocytes (CTLs). CTLs express T cell receptors (TCRs) that specifically recognize the peptide-MHC class I complex. The TCR interaction with the complex triggers the activation of the CTL, leading to the elimination of the infected or cancerous cell. The entire process, from protein degradation to peptide loading and presentation on the cell surface, is tightly regulated and ensures the efficient presentation of endogenous antigens to CTLs. This process is critical for the immune system's ability to detect and eliminate intracellular pathogens and tumor cells.'
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Proteins (1)

Compounds (8)