Lafon Anne, Taranum Surayya, Pietrocola Federico, Dingli Florent, Loew Damarys, Brahma Sandipan, Bartholomew Blaine, Papamichos-Chronakis Manolis
Institut Curie, PSL Research University, CNRS, UMR3664, 26 rue d'Ulm, 75248 Paris, France.
Institut Curie, PSL Research University, Laboratory of Proteomics and Mass Spectrometry, 26 rue d'Ulm, 75248 Paris, France.
Mol Cell. 2015 Dec 3;60(5):784-796. doi: 10.1016/j.molcel.2015.10.028. Epub 2015 Nov 19.
Stalling of RNA Polymerase II (RNAPII) on chromatin during transcriptional stress results in polyubiquitination and degradation of the largest subunit of RNAPII, Rpb1, by the ubiquitin proteasome system (UPS). Here, we report that the ATP-dependent chromatin remodeling complex INO80 is required for turnover of chromatin-bound RNAPII in yeast. INO80 interacts physically and functionally with Cdc48/p97/VCP, a component of UPS required for degradation of RNAPII. Cells lacking INO80 are defective in Rpb1 degradation and accumulate tightly bound ubiquitinated Rpb1 on chromatin. INO80 forms a ternary complex with RNAPII and Cdc48 and targets Rpb1 primed for degradation. The function of INO80 in RNAPII turnover is required for cell growth and survival during genotoxic stress. Our results identify INO80 as a bona fide component of the proteolytic pathway for RNAPII degradation and suggest that INO80 nucleosome remodeling activity promotes the dissociation of ubiquitinated Rpb1 from chromatin to protect the integrity of the genome.
转录应激期间，RNA聚合酶II（RNAPII）在染色质上的停滞会导致RNAPII的最大亚基Rpb1被泛素蛋白酶体系统（UPS）多聚泛素化并降解。在此，我们报告，酵母中依赖ATP的染色质重塑复合体INO80是染色质结合的RNAPII周转所必需的。INO80在物理和功能上与Cdc48/p97/VCP相互作用，Cdc48/p97/VCP是UPS中RNAPII降解所需的一个组分。缺乏INO80的细胞在Rpb1降解方面存在缺陷，并在染色质上积累紧密结合的泛素化Rpb1。INO80与RNAPII和Cdc48形成三元复合物，并靶向准备降解的Rpb1。在基因毒性应激期间，细胞生长和存活需要INO80在RNAPII周转中的功能。我们的结果确定INO80是RNAPII降解蛋白水解途径的一个真正组分，并表明INO80核小体重塑活性促进泛素化Rpb1从染色质上解离，以保护基因组的完整性。
