Uncovering residues that regulate cyclin D1 proteasomal degradation

Q. Feng, D. Sekula, R. Müller, S. J. Freemantle, E. Dmitrovsky

Research output: Contribution to journalArticlepeer-review


Cyclin D1 regulates G1 cell-cycle progression and is aberrantly expressed in carcinogenesis. Proteasomal degradation of cyclin D1 was highlighted as a cancer chemopreventive mechanism. To understand this mechanism better, residues responsible for degradation and ubiquitination of cyclin D1 were investigated. Eighteen lysines in cyclin D1 had single, double or multiple mutations engineered before transfection into BEAS-2B human bronchial epithelial (HBE) cells to evaluate stabilities after all-trans-retinoic acid (RA) or cycloheximide treatments. Specific mutations stabilized cyclin D1, including substitutions of lysines surrounding the cyclin box domain that inhibited RA-mediated degradation and extended the cyclin D1 half-life. Mutation of all cyclin D1 lysines blocked polyubiquitination. N-terminus (but not C-terminus) modification stabilized cyclin D1. Ubiquitination-resistant mutants preferentially localized cyclin D1 to the nucleus, directly implicating subcellular localization in regulating cyclin D1 degradation. Taken together, these findings uncover specific residues conferring ubiquitination of cyclin D1. These provide a mechanistic basis for proteasomal degradation of cyclin D1.

Original languageEnglish (US)
Pages (from-to)5098-5106
Number of pages9
Issue number35
StatePublished - Aug 2 2007
Externally publishedYes


  • All-trans-retinoic acid
  • Cyclin D1
  • Ubiquitination

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research


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