Membrane-anchored ubiquitin-fold protein (IPR017000)

Short name: MUB

Overlapping homologous superfamilies

Family relationships

  • UBL3-like (IPR040015)
    • Membrane-anchored ubiquitin-fold protein (IPR017000)


Ubiquitin-fold proteins are an important class of eukaryotic post-translational modifiers [PMID: 12826404, PMID: 16831869]. They are generally short proteins (less than 200 amino acids) which contain the core beta-grasp fold (also known as the ubiquitin fold) and a C-terminal extension which enables their attachment to other proteins through the terminal carboxyl group. Protein-conjugated ubiquitins have been implicated an a wide variety of cellular process including proteolysis, DNA repair, transcription and autophagy Some ubiquitin-like proteins are not conjugated to proteins, but are instead anchored to the cell membrane by attachment to phospholipids or isoprenes. The functions of these membrane-associated proteins are not generally well understood. In the case of isoprene attachemnet, the prenyl group may also play a role in enhancing protein-protein interactions.

This entry represents a group of membrane-associated ubiquitin-fold proteins found in plants and animals [PMID: 16831869]. In Arabidopsis, membrane-anchored ubiquitin-fold (MUB) proteins recruit and dock specific E2s to the plasma membrane. They appear to interact noncovalently with an E2 surface opposite the active site that forms a covalent linkage with Ub [PMID: 21345795]. The animal homologues of MUBs, also known as UBL3, have also been identified as ubiquitin-like proteins [PMID: 10375635].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.