Tollip is a mediator of protein sumoylation

Alessia Ciarrocchi, Romina D'Angelo, Chiara Cordiglieri, Ada Rispoli, Spartaco Santi, Massimo Riccio, Simona Carone, Anna Laura Mancia, Simone Paci, Elena Cipollini, Davide Ambrosetti, Marialuisa Melli

Research output: Contribution to journalArticlepeer-review

Abstract

Tollip is an interactor of the interleukin-1 receptor involved in its activation. The endosomal turnover of ubiquitylated IL-1RI is also controlled by Tollip. Furthermore, together with Tom1, Tollip has a general role in endosomal protein traffic. This work shows that Tollip is involved in the sumoylation process. Using the yeast two-hybrid technique, we have isolated new Tollip partners including two sumoylation enzymes, SUMO-1 and the transcriptional repressor Daxx. The interactions were confirmed by GST-pull down experiments and immunoprecipitation of the co-expressed recombinants. More specifically, we show that the TIR domain of the cytoplasmic region of IL-1RI is a sumoylation target of Tollip. The sumoylated and unsumoylated RanGAP-1 protein also interacts with Tollip, suggesting a possible role in RanGAP-1 modification and nuclear-cytoplasmic protein translocation. In fact, Tollip is found in the nuclear bodies of SAOS-2/1L-1RI cells where it colocalizes with SUMO-1 and the Daxx repressor. We conclude that Tollip is involved in the control of both nuclear and cytoplasmic protein traffic, through two different and often contrasting processes: ubiquitylation and sumoylation.

Original languageEnglish
Article numbere4404
JournalPLoS One
Volume4
Issue number2
DOIs
Publication statusPublished - Feb 9 2009

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

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