HLA-A specific activating MHC class I receptor activity

Definition

Target type: molecularfunction

Combining with a MHC class I molecule of the HLA-A subclass to mediate signaling that activates a lymphocyte. [GOC:add, GOC:mah, PMID:11929129, PMID:9368779]

HLA-A specific activating MHC class I receptor activity represents a crucial component of the immune system, specifically in the recognition and response to viral and other intracellular pathogens. This molecular function involves the following steps:

1. **Antigen Processing and Presentation:** The HLA-A molecule, a type of MHC class I protein, presents peptides derived from intracellular proteins, including viral proteins, to T cells. This process begins with the degradation of intracellular proteins by the proteasome. The resulting peptides are transported into the endoplasmic reticulum (ER) where they bind to HLA-A molecules.

2. **T Cell Recognition:** The HLA-A-peptide complex translocates to the cell surface, where it interacts with the T cell receptor (TCR) on cytotoxic T lymphocytes (CTLs). The TCR, a highly specific receptor, recognizes the peptide presented by HLA-A.

3. **Signal Transduction:** Upon TCR binding, a cascade of signaling events is triggered within the CTL. These signals involve the activation of various intracellular signaling molecules, culminating in the production of cytokines and the expression of effector molecules.

4. **Effector Function:** The activated CTL, now primed for action, recognizes and eliminates infected cells. This elimination occurs through the release of cytotoxic granules, which contain molecules such as perforin and granzyme. Perforin creates pores in the cell membrane, allowing granzyme to enter and induce apoptosis, or programmed cell death, in the infected cell.

5. **Immune Response:** This specific interaction between HLA-A, the presented peptide, and the TCR is fundamental to the adaptive immune response. It allows for the recognition and elimination of infected cells, contributing to the overall control and clearance of viral infections.
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Proteins (1)

Compounds (10)