MARCH1

MARCH1 is a member of the MARCH family of membrane-bound E3 ubiquitin ligases (EC 6.3.2.19). MARCH proteins add ubiquitin (see MIM 191339) to target lysines in substrate proteins, thereby signaling their vesicular transport between membrane compartments. MARCH1 downregulates the surface expression of major histocompatibility complex (MHC) class II molecules (see MIM 142880) and other glycoproteins by directing them to the late endosomal/lysosomal compartment (Bartee et al., 2004 [PubMed 14722266]; Thibodeau et al., 2008 [PubMed 18389477]; De Gassart et al., 2008 [PubMed 18305173]).[supplied by OMIM, Mar 2010]

Full Name

membrane-associated ring finger (C3HC4) 1

Function

E3 ubiquitin-protein ligase that mediates ubiquitination of TFRC, CD86, FAS and MHC class II proteins, such as HLA-DR alpha and beta, and promotes their subsequent endocytosis and sorting to lysosomes via multivesicular bodies. By constitutively ubiquitinating MHC class II proteins in immature dendritic cells, down-regulates their cell surface localization thus sequestering them in the intracellular endosomal system.

Biological Process

Antigen processing and presentation of peptide antigen via MHC class II Source: UniProtKB
Immune response Source: UniProtKB
Protein polyubiquitination Source: UniProtKB

Cellular Location

Plasma membrane
Cell membrane
Endosome
Late endosome membrane
Early endosome membrane
Lysosome
Lysosome membrane
Golgi apparatus
trans-Golgi network membrane
Other locations
Cytoplasmic vesicle membrane

PTM

Has a short half-life. Instability/short half-life permits rapid changes that allow efficient induction of antigen presentation once antigen presenting cells, APCs, receive maturation signals. Small changes in protein levels significantly alter the cell surface display of MHC class II proteins (By similarity).