SKP2 and telomere syndrome: The results suggest that RCC1 depletion might inhibit and delay the nucleo-cytoplasmic shuttling of Skp2 in early G1 phase to ensure sufficient ubiquitination of Skp2 by APC/C-CDH1 [7, 8], followed by more efficient proteasomal degradation of Skp2 in cytoplasmic portion of STS cells.