major histocompatibility complex class I-related gene protein; MHC class-I related-gene protein; class I histocompatibility antigen-like protein (MR1)

Function

• has antigen presentation function
• involved in development & expansion of MAIT cells
• expression & MAIT cell recognition seem to be ligand- dependent
• heterodimerizes with B2M; this interaction is required for surface expression
• associated with the peptide-loading complex, TAPBP, CALR & PDIA3

Structure

• N-glycosylated
• the alpha-3 region & to a lesser extent the transmembrane domain & cytosolic domain regulate surface expression
• belongs to the MHC class I family
• contains 1 Ig-like C1-type domain (immunoglobulin-like domain)
• MR1 is detected in an open versus folded conformation
• only the folded MR1 conformer activates MAIT cells

Compartment

• membrane
• endoplasmic reticulum
• isoform 4: secreted

Alternative splicing

named isoforms=4

Expression

ubiquitous

Polymorphism

MR1 is not polymorphic

More general terms

• glycoprotein
• membrane protein

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3140
• UniProt: http://www.uniprot.org/uniprot/Q95460.html