ubikvitiinligaaside perekond, kuhu kuuluvad mitmed erisuguste valkude kompleksid, Skp, Cullin, F-box containing complex (or SCF complex) is a multi-protein E3 ubiquitin ligase complex catalyzing the ubiquitination of proteins destined for proteasomal degradation. It has important roles in the ubiquitination of proteins involved in the cell cycle, controlling the transitions between G1/S and G2/M phases.