ARTS-1

Type 1 tumor necrosis factor receptor shedding aminopeptidase regulator, also known as endoplasmic reticulum aminopeptidase 1 (ARTS-1), is a is_associated_with::protein which in humans is encoded by the ARTS-1 is_associated_with::gene.

Endoplasmic reticulum amino peptidase 1 is active in the is_associated_with::endoplasmic reticulum, which is involved in protein processing and transport. This protein is an is_associated_with::aminopeptidase, which is an enzyme that cleaves other proteins into smaller fragments called peptides.

Nomenclature
ARTS1 is also known as:
 * ER aminopeptidase 1 (ERAP1) the name accepted by the Hugo Gene Nomenclature Committee
 * ER aminopeptidase associated with antigen processing (ERAAP)
 * Adipocyte-derived leucine aminopeptidase (ALAP)
 * Puromycin-insensitive leucine aminopeptidase (PILS-AP)

Function
ERAP1 has two major functions in the immune system:


 * First, ERAP1 cleaves several proteins called is_associated_with::cytokine receptors on the surface of cells. Cleaving these receptors reduces their ability to transmit chemical signals into the cell, which affects the process of is_associated_with::inflammation.


 * Second, ERAP1 trims peptides within the endoplasmic reticulum so that they can be loaded onto is_associated_with::major histocompatibility complex (MHC) class I. These peptides are attached to MHC class I in the endoplasmic reticulum and exported to the cell surface, where they are displayed to the immune system. If the immune system recognizes the peptides as foreign (such as viral or bacterial peptides), it responds by triggering the infected cell to self-destruct.

ARTS-1 is a member of the M1 family of zinc metallopeptidases which acts as an is_associated_with::aminopeptidase that degrades oligopeptides by cleavage starting at the amino terminus. One of the functions of aminopeptidases is to degrade potentially toxic peptides in the is_associated_with::cytosol.

ARTS-1 is a transmembrane protein that is localized to the is_associated_with::endoplasmic reticulum. It has been implicated in the following functions:
 * Shedding of various is_associated_with::cytokine receptors and decoy receptors
 * Trimming of antigenic peptides before binding to is_associated_with::MHC class I, affecting antigen presentation to cytotoxic T lymphocytes

Clinical significance
Aminopeptidases play a role in the metabolism of several peptides that may be involved in is_associated_with::blood pressure and the is_associated_with::pathogenesis of essential hypertension. Mutations in the ARTS-1 have been linked to an increased risk of is_associated_with::ankylosing spondylitis but only in is_associated_with::HLA-B27 positive patients.

The protein encoded by this gene is an aminopeptidase involved in trimming HLA class I-binding precursors so that they can be presented on MHC class I molecules. The encoded protein acts as a is_associated_with::monomer or as a is_associated_with::heterodimer with ERAP2. This protein may also be involved in blood pressure regulation by inactivation of is_associated_with::angiotensin II. Three transcript variants encoding two different is_associated_with::isoforms have been found for this gene.