Core component of multiple SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes which mediate the ubiquitination of proteins involved in cell cycle progression, signal transduction and transcription. Through the RING-type zinc finger, seems to recruit the E2 ubiquitination enzyme to the complex and brings it into close proximity to the substrate. Required for the specific SCF-dependent proteolysis of CI, but not that of ARM, suggesting that it also participates in the selection of substrates inside the SCF complex (PubMed:12062088). During early metamorphosis, part of the SCF-slmb complex that negatively regulates the InR/PI3K/TOR pathway to activate the pruning of unnecessary larval ddaC dendrites and mushroom body axons (PubMed:24068890). The SCF-slmb complex also regulates asymmetrical division of neuroblasts and inhibits ectopic neuroblast formation partly through SAK and Akt1 (PubMed:24413555). Also part of an SCF complex required for caspase activation during sperm differentiation (Probable). Protein modification; protein ubiquitination. Component of SCF E3 ubiquitin-protein ligase complexes consisting of Skpa, Cul1, Roc1a and an F-box protein. In larvae neuroblast self renewal and asymmetric division, as well as ddaC dendrite and mushroom body axon pruning, the complex contains the F-box protein slmb (SCF-slmb) (PubMed:24068890, PubMed:24413555). Interacts directly with Cul1 and Slmb (PubMed:11500045). In caspase activation during sperm differentiation, the complex contains the F-box protein ntc (Probable). Widely expressed. Expressed in embryonic, larval and adult tissues. Expressed both maternally and zygotically. The RING-type zinc finger domain is essential for ubiquitin ligase activity. It coordinates an additional third zinc ion (By similarity). Severe pruning defect in ddaC neurons (PubMed:24068890). Also shows defects in ddaD and ddaE neuron pruning and in ddaF apoptosis (PubMed:24068890). RNAi-mediated knockdown results in apical detachment of scolopidial cells in Johnston's organ (PubMed:27331610). Belongs to the RING-box family.