The glomuvenous malformation protein Glomulin binds Rbx1 and regulates cullin RING ligase-mediated turnover of Fbw7

Mol Cell. 2012 Apr 13;46(1):67-78. doi: 10.1016/j.molcel.2012.02.005. Epub 2012 Mar 8.


Fbw7, a substrate receptor for Cul1-RING-ligase (CRL1), facilitates the ubiquitination and degradation of several proteins, including Cyclin E and c-Myc. In spite of much effort, the mechanisms underlying Fbw7 regulation are mostly unknown. Here, we show that Glomulin (Glmn), a protein found mutated in the vascular disorder glomuvenous malformation (GVM), binds directly to the RING domain of Rbx1 and inhibits its E3 ubiquitin ligase activity. Loss of Glmn in a variety of cells, tissues, and GVM lesions results in decreased levels of Fbw7 and increased levels of Cyclin E and c-Myc. The increased turnover of Fbw7 is dependent on CRL and proteasome activity, indicating that Glmn modulates the E3 activity of CRL1(Fbw7). These data reveal an unexpected functional connection between Glmn and Rbx1 and demonstrate that defective regulation of Fbw7 levels contributes to GVM.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cullin Proteins / genetics
  • Cullin Proteins / metabolism*
  • Cyclin E / genetics
  • Cyclin E / metabolism
  • F-Box Proteins / genetics
  • F-Box Proteins / metabolism*
  • F-Box-WD Repeat-Containing Protein 7
  • Glomus Tumor / genetics
  • Glomus Tumor / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Paraganglioma, Extra-Adrenal / genetics
  • Paraganglioma, Extra-Adrenal / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination*


  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Cell Cycle Proteins
  • Cullin 1
  • Cullin Proteins
  • Cyclin E
  • F-Box Proteins
  • F-Box-WD Repeat-Containing Protein 7
  • FBXW7 protein, human
  • GLMN protein, human
  • MYC protein, human
  • Proto-Oncogene Proteins c-myc
  • RBX1 protein, human
  • Ubiquitin-Protein Ligases

Supplementary concepts

  • Glomus vagale tumors