HLA-A

Also known as HLAA, Aw-33, Aw-74, major histocompatibility complex, class I, A, HLA-A11, HLA-A33, HLA-DQB1, HLA-DRB1

HLA-A is a group of human leukocyte antigens (HLA) that are encoded by the HLA-A locus, which is located at human chromosome 6p21.3. HLA is a major histocompatibility complex (MHC) antigen specific to humans. HLA-A is one of three major types of human MHC class I transmembrane proteins. The others are HLA-B and HLA-C. The protein is a heterodimer, and is composed of a heavy α chain and smaller β chain. The α chain is encoded by a variant HLA-A gene, and the β chain (β2-microglobulin) is an invariant β2 microglobulin molecule. The β2 microglobulin protein is encoded by the B2M gene, which is lo

Key facts

Heteropolypeptide.heteropolymer: MHC class I, A
Heteropolypeptide.polymer_type: heterodimer
Heteropolypeptide.protein_type: Transmembrane protein
Heteropolypeptide.function: Peptide presentation for immune recognition
Heteropolypeptide.image: Illustration_HLA-A.png
Heteropolypeptide.image_source: Illustration of HLA-A
Heteropolypeptide.SubunitCount: 2
Heteropolypeptide.subunit1: α
Heteropolypeptide.gene1: HLA-A
Heteropolypeptide.locus1: Chromosome 6p21.3
Heteropolypeptide.subunit2: β2M
Heteropolypeptide.gene2: B2M

Article

11 sections

Contents

''HLA-A'' gene
Alleles
Protein
Function
Natural function
Other activities
Role in disease
{{anchor|HIV/AIDS}} HIV/AIDS
Summary
References
External links

MHC Class I molecules such as HLA-A participate in a process that presents short polypeptides to the immune system. These polypeptides are typically 7–11 amino acids in length and originate from proteins being expressed by the cell. There are two classes of polypeptide that can be presented by an HLA protein: those that are supposed to be expressed by the cell (self) and those of foreign derivation (non-self). Under normal conditions cytotoxic T cells, which normally patrol the body in the blood, "read" the peptide presented by the complex. T cells, if functioning properly, only bind to non-self peptides. If binding occurs, a series of events is initiated culminating in cell death via apoptosis. In this manner, the human body eliminates any cells infected by a virus or expressing proteins they shouldn't be (e.g. cancerous cells).