A role for SUMOylation in snoRNP biogenesis revealed by quantitative proteomics

作者：Westman Belinda J; Lamond Angus I^*

来源：Nucleus-Austin, 2011, 2(1): 30-37.

DOI：10.4161/nucl.2.1.14437

• nucleolus
• SUMO
• Nop5/Nop58
• snoRNA
• snoRNP
• SILAC

A role for SUMOylation in the biogenesis and/or function of Box C/D snoRNPs has been reported, mediated via SUMO2 conjugation to the core snoRNP protein, Nop58. A quantitative proteomics screen, based on SILAC (stable-isotope labeling by amino acids in cell culture) and mass spectrometry using extracts prepared from cultured mammalian cells expressing either 6His-SUMO1 or -SUMO2, revealed that the snoRNP-related proteins Nop58, Nhp2, DKC1 and NOLC1 are amongst the main SUMO-modified proteins in the nucleolus. SUMOylation of Nhp2 and endogenous Nop58 was confirmed using a combination of in vitro and cell-based assays and the modified lysines identified by site-directed mutagenesis. SUMOylation of Nop58 was found to be important for high-affinity Box C/D snoRNA binding and the localization of newly transcribed snoRNAs to the nucleolus. Here, these findings are reviewed and a model for understanding Nop58 SUMOylation in the context of Box C/D snoRNP biogenesis is presented. Given the essential role of snoRNPs in the modification of pre-ribosomal RNA, this work suggests that SUMO, snoRNPs and ribosome assembly, and thus cellular translation, growth and proliferation, may be linked via novel mechanisms which warrant further investigation.

• 出版日期2011-2