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 (By similarity). Interacts with ADO3/FKF1, EBF1, PP2A13, SKIP15, SKIP16, CPR1/CPR30, At1g55000, At3g61590, At1g67340, At1g78100, At3g04660, At4g38940, At4g39550 and At5g49610. Mostly expressed in inflorescences, and, to a lower extent, in seedlings and siliques. Also detected in cotyledons, leaves, pollen and seeds. Belongs to the SKP1 family.