Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex required for synaptic transmission (PubMed:19782033). The BCR(KCTD13) E3 ubiquitin ligase complex mediates the ubiquitination of RHOA, leading to its degradation by the proteasome (PubMed:19782033) Degradation of RHOA regulates the actin cytoskeleton and promotes synaptic transmission (By similarity). Protein modification; protein ubiquitination. Homotetramer; forms a two-fold symmetric tetramer in solution (PubMed:28963344). Interacts with CUL3; interaction is direct and forms a 5:5 heterodecamer (PubMed:28963344). Component of the BCR(KCTD13) E3 ubiquitin ligase complex, at least composed of CUL3, KCTD13/BACURD1 and RBX1. Interacts with RHOA; with a preference for RhoA-GDP (PubMed:19782033). Interacts with POLD2 and PCNA (PubMed:11593007). Interacts with SPRTN (PubMed:22902628). Expressed in a wide variety of tissues. By TNF and IL6/interleukin-6. The gene represented in this entry may act as a disease modifier for autism and schizophrenia associated with recurrent deletions and duplications of chromosome 16p11.2 region (PubMed:22596160, PubMed:25695269). Belongs to the BACURD family. Baed on animal models in mouse and zebrafish, it was suggested that KCTD13 is the major factor inducing the macrocephaly phenotype associated with the 16p11.2 deletion (PubMed:22596160). However, a subsequent report showed that KCTD13 does not play a role in brain size.