KCTD7

Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex that mediates the ubiquitination of multiple substrates, leading to either their proteasomal or lysosomal degradation, or modulating their activity through non-degradative ubiquitination. Regulates voltage-gated potassium channels, thereby modulating hyperpolarizing potassium currents in neurons and inducing potassium-dependent membrane hyperpolarization. Also regulates the neuronal glutamine transporter SLC38A2/SAT2, influencing neurotransmitter precursor availability. Regulates calpain activity via atypical, non-degradative ubiquitination by mediating ubiquitination of CAPN1 via 'Lys6'-, 'Lys27'-, 'Lys29'-, and 'Lys63'-linked chains, and CAPN2 via 'Lys6'-linked chains, thereby preventing calpain autolysis. Promotes lysosomal enzyme trafficking and maintains lysosomal function by acting as an endogenous regulator of CLN5, enhancing its ubiquitination and proteasomal degradation..

Function from UniProtKB (Q96MP8), read 2026-09-23. CC BY 4.0.