HM13
Encyclopedia
Minor histocompatibility antigen H13 is a protein
that in humans is encoded by the HM13 gene
.
by the proteasome
, enters the endoplasmic reticulum
(ER) lumen by the transporter associated with antigen processing
(TAP) and is presented on the cell surface on H2-Db major histocompatibility anigen I (MHC I) molecules. The alloreactivity, which leads to transplant rejection
in mice, is conferred by Val/Ile polymorphism
in the ‘SSV(V/I)GVWYL’ peptide. The orthologue gene in humans is called HM13. If a related polymorphism exists, and if the HM13 serves as a Minor histocompatibility antigen
, however, remains to be addressed.
The protein encoded by the M13/HM13 gene is the signal peptide peptidase
(SPP), an ER-resident intramembrane protease
.
SPP localizes to the endoplasmic reticulum
, catalyzes intramembrane proteolysis of some signal peptides after they have been cleaved from a preprotein. This activity is required to generate signal sequence-derived human lymphocyte antigen-E epitopes that are recognized by the immune system, and to process hepatitis C virus core protein. The encoded protein is an integral membrane protein with sequence motifs characteristic of the presenilin-type aspartic proteases. Multiple transcript variants encoding several different isoforms have been found for this gene.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that in humans is encoded by the HM13 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Function
The minor histocompatibility antigen 13 is a nonamer peptide that originates from a protein encoded by the H13 gene. The peptide is generated by the cytosolCytosol
The cytosol or intracellular fluid is the liquid found inside cells, that is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into compartments....
by the proteasome
Proteasome
Proteasomes are very large protein complexes inside all eukaryotes and archaea, and in some bacteria. In eukaryotes, they are located in the nucleus and the cytoplasm. The main function of the proteasome is to degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks...
, enters the endoplasmic reticulum
Endoplasmic reticulum
The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...
(ER) lumen by the transporter associated with antigen processing
Transporter associated with antigen processing
Transporter associated with antigen processing is a member of the ATP-binding-cassette transporter family. It delivers cytosolic peptides into the endoplasmic reticulum , where they bind to nascent MHC class I molecules....
(TAP) and is presented on the cell surface on H2-Db major histocompatibility anigen I (MHC I) molecules. The alloreactivity, which leads to transplant rejection
Transplant rejection
Transplant rejection occurs when transplanted tissue is rejected by the recipient's immune system, which destroys the transplanted tissue. Transplant rejection can be lessened by determining the molecular similitude between donor and recipient and by use of immunosuppressant drugs after...
in mice, is conferred by Val/Ile polymorphism
Polymorphism
Polymorphism or dimorphism may refer to:-Biology:* Polymorphism , including:** having multiple phenotypes within a population; the switch that determines which phenotype an individual displays can be genetic or environmental...
in the ‘SSV(V/I)GVWYL’ peptide. The orthologue gene in humans is called HM13. If a related polymorphism exists, and if the HM13 serves as a Minor histocompatibility antigen
Minor histocompatibility antigen
Minor histocompatibility antigen are receptors on the cell surface of donated organs that are known to give an immunological response in some organ transplants. They cause problems of rejection less frequently than those of the major histocompatibility complex .Minor histocompatibility antigens are...
, however, remains to be addressed.
The protein encoded by the M13/HM13 gene is the signal peptide peptidase
Signal Peptide Peptidase
The Signal Peptide Peptidase is an intramembrane aspartyl protease with the conserved active site motifs 'YD' and 'GxGD' in in adjacent transmembrane domains . Its sequences is highly conserved in different vertebrate species...
(SPP), an ER-resident intramembrane protease
Intramembrane protease
Intramembrane proteases are enzymes that have the property of cleaving transmembrane domains of integral membrane proteins. All known intramembrane proteases are themselves integral membrane proteins with multiple transmembrane domains, and they have their active sites buried within the lipid...
.
SPP localizes to the endoplasmic reticulum
Endoplasmic reticulum
The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...
, catalyzes intramembrane proteolysis of some signal peptides after they have been cleaved from a preprotein. This activity is required to generate signal sequence-derived human lymphocyte antigen-E epitopes that are recognized by the immune system, and to process hepatitis C virus core protein. The encoded protein is an integral membrane protein with sequence motifs characteristic of the presenilin-type aspartic proteases. Multiple transcript variants encoding several different isoforms have been found for this gene.