Substrate recognition component of a SCF-like ECS (Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:15601820, PubMed:21199876). Negatively regulates nitric oxide (NO) production and limits cellular toxicity in activated macrophages by mediating the ubiquitination and proteasomal degradation of NOS2 (PubMed:21199876). Acts as a bridge which links NOS2 with the ECS E3 ubiquitin ligase complex components ELOC and CUL5 (PubMed:21199876). {ECO:0000269|PubMed:15601820, ECO:0000269|PubMed:21199876}. This is the function of SPSB1 (splA/ryanodine receptor domain and SOCS box containing 1, ENSG00000171621).