RHOBTB3, like other RHOBTB family members, RHOBTB1 and RHOBTB2, binds CUL3 (cullin 3) a core component of BTB:CUL3:RBX1 E3 ubiquitin ligase complexes (Berthold et al. 2008). The following proteins are substrates of RHOBTB3-dependent ubiquitin ligase complexes: RAB9A, RAB9B (Espinosa et al. 2009) Cyclin E1 (Lu and Pfeffer 2013) LRRC41 (MUF1) (Schenková et al. 2012).
The following proteins bind directly to RHOBTB3 but there is no evidence that they are substrates of RHOBTB3-dependent ubiquitin ligase complexes: HGS (HRS) (Pridgeon et al. 2009) PLIN3 (TIP47) (Espinosa et al. 2009) 5-HT7a serotonin receptor (Matthys et al. 2012) VHL (Zhang et al. 2015).