Both negative and positive G1 cell cycle regulators undergo proteasome-dependent degradation during sucrose starvation in Arabidopsis

Figures & data

Figure 1 Model of G₁-phase arrest after sucrose starvation. (A) Under normal sucrose conditions, RBR represses transcription by binding E2Fs during early G1 phase. However, CDKA/CYCD3 phosphorylates RBR during late G₁ phase, which results in releasing a functional E2F-DP to activate target genes involved in progression into S phase. (B) During sucrose starvation, CYCD3;1 undergoes proteasome-dependent degradation and disappears rapidly within several minutes. However, both AtRBR1 and E2Fs also undergo proteasome-dependent degradation, and this may be required for G₁-phase arrest after prolonged sucrose starvation.