Membrane-anchored Ub-fold(MUBs) is a family of ubiquitin-fold proteins that are plasma membrane-anchored by prenylation.MUB proteins present in animals, filamentous fungi, and plants. Extending from the C terminus of the Ub-fold is typically a cysteine-containing CAAX (where A indicates aliphatic amino acid) sequence that can direct the attachment of either a 15-carbon farnesyl or a 20-carbon geranylgeranyl moiety in vitro (1).

1. Downes BP, Saracco SA, Lee SS, Crowell DN, Vierstra RD (2006). MUBs, a family of ubiquitin-fold proteins that are plasma membrane-anchored by prenylation. Trends in Biochemical Sciences., 281(37):27145-57. PMID:16831869