Core component of the CTLH E3 ubiquitin-protein ligase complex that selectively accepts ubiquitin from UBE2H and mediates ubiquitination and subsequent proteasomal degradation of target proteins (By similarity). Acts as a positive regulator of Wnt signaling pathway by promoting beta-catenin (CTNNB1) nuclear accumulation (By similarity). Required for normal Wnt signaling and normal dorsoventral patterning during embryogenesis (PubMed:28829046). Identified in the CTLH complex that contains at least MAEA, RMND5A (or alternatively its paralog RMND5B), GID8, WDR26, and RANBP9 and/or RANBP10. Interacts with CTNNB1. Expressed in the early developmental stages of embryos. Morpholino knockdown produces morphants which exhibit loss or reduction of dorsal embryonic structures and Wnt signaling deficiency. Belongs to the GID8 family.