FUBI/MNSF beta: ProductsThe Ubiquitin-like Protein Finkel-Biskis-Reilly Murine Sarcoma Virus (FUBI), also known as Monoclonal Nonspecific Suppressor Factor beta (MNSF beta), is a 74 amino acid (aa) Ubiquitin-like protein modifier with a predicted molecular weight of 8 kDa that is encoded by the FAU gene. FUBI/MNSF beta is translated as a fusion protein with the ribosomal protein S30; the fusion protein is post-translationally cleaved into two functional proteins. The mouse and rat FUBI/MNSF beta-ribosomal protein S30 fusion orthologs share 97% and 98% aa sequence identity with the human protein, respectively. Like many Ubiquitin-like proteins, FUBI/MNSF beta contains a C-terminal Gly-Gly motif and can be covalently conjugated to acceptor proteins to form adducts that modulate protein action. For example, FUBI/MNSF beta conjugation to Bcl-G inhibits the ERK1/ERK2 cascade downstream of TLR4 activation in macrophage cell lines. Additionally, FUBI/MNSF beta conjugation to Endophilin II has been shown to regulate Dectin-1-mediated phagocytosis and inflammation. The role of FUBI/MNSF beta downstream of TLR2 signaling is unclear, however novel FUBI/MNSF beta adducts may contribute to TLR2 signaling, as silencing of FUBI/ MNSF beta enhanced signaling via a TLR2-specific ligand.