Involved in ubiquitination and subsequent proteasomal degradation of target proteins. Together with CUL1, RBX1 and a F-box protein, it forms a SCF E3 ubiquitin ligase complex. The functional specificity of this complex depends on the type of F-box protein. In the SCF complex, it serves as an adapter that links the F-box protein to CUL1 (By similarity). Protein modification; protein ubiquitination. Part of a SCF (SKP1-cullin-F-box) protein ligase complex. Expressed at low levels in seedlings and leaves. Highly expressed in the pith and vascular bundle in the stem. Found in the pedicel of young buds. Also expressed in the inner epidermis of carpels and pedicels in mature flowers. In siliques, mostly expressed in inner epidermis of the valve. Belongs to the SKP1 family.