SPSB3

Substrate-recognition component of a cullin-5-RING E3 ubiquitin-protein ligase complex (ECS complex, also named CRL5 complex), which mediates the ubiquitination and subsequent proteasomal degradation of target proteins, such as CGAS and SNAI1. The ECS(SPSB3) complex catalyzes 'Lys-48'-linked ubiquitination of nuclear CGAS in cycling cells, leading to its degradation. Recognizes and binds nucleosome-bound CGAS: ubiquitination and degradation of nuclear CGAS during G1 and G2 phases is required to promote low intranuclear CGAS abundance before the next mitotic cycle. The ECS(SPSB3) complex also mediates ubiquitination and degradation of phosphorylated SNAI1..

Function from UniProtKB (Q6PJ21), read 2026-09-23. CC BY 4.0.