E3 ubiquitin-protein ligase MGRN1; Mahogunin RING finger protein 1; RING finger protein 156 (MGRN1, KIAA0544, RNF156)

Function

• E3 ubiquitin-protein ligase (putative)
• ubiquitin conjugation, 3rd step
• mediates monoubiquitination at multiple sites of TSG101 in the presence of UBE2D1
• does not mediate ubiquitination of UBE2G1, nor UBE2H
• role in regulation of endosome-to-lysosome trafficking
• impairs MC1R- & MC4R-signaling by competing with GNAS-binding to MCRs & inhibiting agonist-induced cAMP production
• does not inhibit ADRB2-signaling
• does not promote MC1R ubiquitination
• autoubiquitinated in vitro (putative)
• interacts with MC1R & MC4R
• does not interact with TBXA2R
• interacts with mislocalized cytosolically exposed PRNP
  • interaction alters MGRN1 subcellular location & causes lysosomal enlargement (putative)

Structure

• the RING finger is required for ubiquitin ligase activity
• contains 1 RING-type Zn+2 finger

Compartment

• early endosome
  • endosomal localization is dependent on the interaction with TSG101
• isoforms 1 & 2:
  • cytoplasm, nucleus
  • translocation from the cytosol to the nucleus is seen only in the presence of MC1R & MC4R
  • excluded from nucleoli
• isoform 3 & 4 : cytoplasm, cell membrane

Alternative splicing

named isoforms=4

More general terms

• E3 ubiquitin ligase
• ring finger protein
• myristoylated protein
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=23295
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:23295
• OMIM: https://mirror.omim.org/entry/607559
• UniProt: http://www.uniprot.org/uniprot/O60291.html