Major histocompatibility complex, class II, DP alpha 1, also known as HLA-DPA1, is a human
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Function
The
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
encoded by this gene belongs to the
HLA class II alpha chain
paralogues
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a s ...
. The class II molecule is a heterodimer consisting of an alpha (DPA) and a beta chain (DPB), both anchored in the membrane. It plays a central role in the
immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splint ...
by presenting peptides derived from extracellular proteins. Class II molecules are expressed in
antigen-presenting cells (APC: B lymphocytes, dendritic cells, macrophages).
Gene structure and polymorphisms
The alpha chain is approximately 33-35 kDa. It is encoded by 5
exons, exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular
domains, exon 4 encodes the
transmembrane
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequent ...
and the
cytoplasmic tail. Within the DP molecule both the alpha chain and the beta chain contain the
polymorphisms specifying the peptide binding specificities, resulting in up to 4 different molecules.
See also
*
Major histocompatibility complex
*
Human leukocyte antigen
The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of th ...
*
HLA-DP
HLA-DP is a protein/peptide-antigen receptor and graft-versus-host disease antigen that is composed of 2 subunits, DPα and DPβ. DPα and DPβ are encoded by two loci, HLA-DPA1 and HLA-DPB1, that are found in the MHC Class II (or HLA-D) regio ...
References
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