Ubiquitin proteomics identifies RNA polymerase I as a target of the Smc5/6 complex

Ubiquitin proteomics identifies RNA polymerase I as a target of the Smc5/6 complex

Blog Article

Summary: Ubiquitination controls numerous cellular processes, and its deregulation is associated with many pathologies.The Nse1 subunit in the Smc5/6 complex contains a RING domain with ubiquitin E3 ligase activity and essential functions in genome integrity.However, Nse1-dependent ubiquitin targets remain elusive.Here, we use label-free quantitative proteomics to analyze the nuclear ubiquitinome of nse1-C274A RING mutant cells.

Our Defrost Cutout Thermostat results show that Nse1 impacts the ubiquitination of several proteins involved in ribosome biogenesis and metabolism that, importantly, extend beyond canonical functions of Smc5/6.In addition, our analysis suggests a connection between Nse1 and RNA polymerase I (RNA Pol I) ubiquitination.Specifically, Nse1 and the Smc5/6 complex promote ubiquitination of K408 and K410 in the clamp domain of Rpa190, a modification that induces its degradation in response to blocks in transcriptional elongation.We propose that Floor Brushes this mechanism contributes to Smc5/6-dependent segregation of the rDNA array, the locus transcribed by RNA Pol I.