Rho-related BTB domain-containing protein 3 (RHOBTB3, KIAA0878)

Function

• Rab9-regulated ATPase required for endosome to Golgi transport
• role in transport vesicle docking at the Golgi complex, possibly by participating to release M6PRBP1/TIP47 from vesicles to permit their efficient docking & fusion at the Golgi
• specifically binds Rab9, but not other Rab proteins
• has low intrinsic ATPase activity due to autoinhibition, which is relieved by Rab9
• interacts with RAB9A & RAB9B (at lower level compared to RAB9A-binding)
• interacts with M6PRBP1/TIP47

Kinetic parameters:

• KM=48 uM for ATP

Structure

• although predicted to be a GTP-binding protein because of the presence of a Rho-like region, binds & hydrolyzes ATP
• in contrast to Rho-like proteins, the conserved Asp in position 138 in the G4 region is replaced by an Asn, decreasing the ability to bind GTP
• contains 2 BTB/POZ domains

Compartment

Golgi

Expression

• ubiquitous
• highly expressed in neural & cardiac tissues, pancreas, placenta & testis

More general terms

• Rho-related BTB domain-containing protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=22836
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:22836
• OMIM: https://mirror.omim.org/entry/607353
• UniProt: http://www.uniprot.org/uniprot/O94955.html