Component of the SCF (SKP1-CUL1-F-box protein) E3 ubiquitin ligase complex, which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. The SCF complex plays a crucial role in regulating response to auxin and is essential for growth and development. 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 (By similarity). Protein modification; protein ubiquitination. Part of SCF complexes, which consist of a SKP1-related protein, a cullin, a RBX protein and a F-box protein. Not detected in floral buds, stems and roots. The RING-type zinc finger domain is essential for ubiquitin ligase activity. It coordinates an additional third zinc ion. Belongs to the RING-box family.