During ubiquitin-mediated protein degradation in various events of cell cycle, ubiquitin-protein ligases ubiquitinylate substrate proteins, marking them for degradation by proteasomes. Cyclins are degraded through the action of two different ubiquitin-protein ligases, SCF and the anaphase-promoting complex or cyclosome. Following statements are regarding to SCF and APC/C. A. SCF controls the G1–S phase transition by degrading G1/S phase cyclins and, CDK inhibitory proteins. B. APC/C degrades S phase and mitotic cyclins, thereby promoting the exit from mitosis. C. SCF and APC/C are multi-subunit ubiquitin-protein ligases that belong to the RING finger family of ubiquitin protein ligases. D. SCF and APC/C belong to the different ubiquitin-protein ligase family, their regulation is same. E. SCF recognizes its substrates only when they are phosphorylated. F. SCF and APC/C both recognizes its substrates only when they are phosphorylated. Which of the following is incorrect? -triyambak.org