Other Publications (1)
Articles by Fengxi Meng in JoVE
In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells Fengxi Meng*1,2, Xiaofeng Li*1,2, Hui Ren1,2, Jiang Qian1,2 1Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 2Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University Small ubiquitin-related modifier (SUMO) family proteins are conjugated to the lysine residues of target proteins to regulate various cellular processes. This paper describes a protocol for the detection of retinoblastoma (Rb) protein SUMOylation under endogenous and exogenous conditions in human cells.
Other articles by Fengxi Meng on PubMed
SUMOylation of Rb Enhances Its Binding with CDK2 and Phosphorylation at Early G1 Phase Cell Cycle (Georgetown, Tex.). | Pubmed ID: 27163259 Retinoblastoma protein (Rb) is a prototypical tumor suppressor that is vital to the negative regulation of the cell cycle and tumor progression. Hypo-phosphorylated Rb is associated with G0/G1 arrest by suppressing E2F transcription factor activity, whereas Rb hyper-phosphorylation allows E2F release and cell cycle progression from G0/G1 to S phase. However, the factors that regulate cyclin-dependent protein kinase (CDK)-dependent hyper-phosphorylation of Rb during the cell cycle remain obscure. In this study, we show that throughout the cell cycle, Rb is specifically small ubiquitin-like modifier (SUMO)ylated at early G1 phase. SUMOylation of Rb stimulates its phosphorylation level by recruiting a SUMO-interaction motif (SIM)-containing kinase CDK2, leading to Rb hyper-phosphorylation and E2F-1 release. In contrast, a SUMO-deficient Rb mutant results in reduced SUMOylation and phosphorylation, weakened CDK2 binding, and attenuated E2F-1 sequestration. Furthermore, we reveal that Rb SUMOylation is required for cell proliferation. Therefore, our study describes a novel mechanism that regulates Rb phosphorylation during cell cycle progression.