second BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Rho-related BTB domain-containing protein 3 (RhoBTB3)
RhoBTB3 is an atypical Rho family small guanosine triphosphatase (GTPase) and is a member of the RhoBTB subfamily, which is characterized by containing a GTPase domain (in most cases, non-functional) followed by a proline-rich region, tandem BTB domains, and a conserved C-terminal region. The carboxyl terminal extension that harbors two BTB domains is capable of assembling cullin 3-dependent ubiquitin ligase complexes. RhoBTB3 is a Golgi-associated Rho-related ATPase that regulates the S/G2 transition of the cell cycle by targeting cyclin E for ubiquitylation. It is involved in vesicle trafficking and in targeting proteins for degradation in the proteasome. It binds directly to Rab9 GTPase and functions with Rab9 in protein transport from endosomes to the trans Golgi network. It also promotes proteasomal degradation of Hypoxia-inducible factor alpha (HIFalpha) through facilitating hydroxylation and suppresses the Warburg effect. This model corresponds to the second BTB domain. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.
Jiyao W et al.(2023). "The conserved domain database in 2023.",