2. Academic Validation
  3. Two Distinct Types of E3 Ligases Work in Unison to Regulate Substrate Ubiquitylation

Two Distinct Types of E3 Ligases Work in Unison to Regulate Substrate Ubiquitylation

  • Cell. 2016 Aug 25;166(5):1198-1214.e24. doi: 10.1016/j.cell.2016.07.027.
Daniel C Scott 1,  David Y Rhee 2,  David M Duda 1,  Ian R Kelsall 3,  Jennifer L Olszewski 4,  Joao A Paulo 2,  Annemieke de Jong 5,  Huib Ovaa 6,  Arno F Alpi 3,  J Wade Harper 7,  Brenda A Schulman 8
Affiliations

Affiliations

  • 1 Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
  • 2 Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
  • 3 MRC Protein Phosphorylation and Ubiquitylation Unit, Dundee DD1 5EH, UK.
  • 4 Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
  • 5 Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands.
  • 6 Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; Department of Chemical Immunology, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands.
  • 7 Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA. Electronic address: [email protected].
  • 8 Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. Electronic address: [email protected].
PMID: 27565346 DOI: 10.1016/j.cell.2016.07.027
Abstract

Hundreds of human cullin-RING E3 Ligases (CRLs) modify thousands of proteins with ubiquitin (UB) to achieve vast regulation. Current dogma posits that CRLs first catalyze UB transfer from an E2 to their client substrates and subsequent polyubiquitylation from various linkage-specific E2s. We report an alternative E3-E3 tagging cascade: many cellular NEDD8-modified CRLs associate with a mechanistically distinct thioester-forming RBR-type E3, ARIH1, and rely on ARIH1 to directly add the first UB and, in some cases, multiple additional individual monoubiquitin modifications onto CRL client substrates. Our data define ARIH1 as a component of the human CRL system, demonstrate that ARIH1 can efficiently and specifically mediate monoubiquitylation of several CRL substrates, and establish principles for how two distinctive E3s can reciprocally control each other for simultaneous and joint regulation of substrate ubiquitylation. These studies have broad implications for CRL-dependent proteostasis and mechanisms of E3-mediated UB ligation.

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