Ubiquitination and degradation of the hominoid-specific oncoprotein TBC1D3 is regulated by protein palmitoylation

Chen Kong, Jeffrey J. Lange, Dmitri Samovski, Xiong Su, Jialiu Liu, Sinju Sundaresan, Philip D. Stahl

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Expression of the hominoid-specific oncoprotein TBC1D3 promotes enhanced cell growth and proliferation by increased activation of signal transduction through several growth factors. Recently we documented the role of CUL7 E3 ligase in growth factors-induced ubiquitination and degradation of TBC1D3. Here we expanded our study to discover additional molecular mechanisms that control TBC1D3 protein turnover. We report that TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. The expression of double palmitoylation mutant TBC1D3:C318/325S resulted in protein mislocalization and enhanced growth factors-induced TBC1D3 degradation. Moreover, ubiquitination of TBC1D3 via CUL7 E3 ligase complex was increased by mutating the palmitoylation sites, suggesting that depalmitoylation of TBC1D3 makes the protein more available for ubiquitination and degradation. The results reported here provide novel insights into the molecular mechanisms that govern TBC1D3 protein degradation. Dysregulation of these mechanisms in vivo could potentially result in aberrant TBC1D3 expression and promote oncogenesis.

Original languageEnglish
Pages (from-to)388-393
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume434
Issue number2
DOIs
StatePublished - May 3 2013

Keywords

  • CUL7
  • Cancer
  • Growth factor receptor signaling
  • Hominoid-specific proteins
  • Oncogene
  • Protein degradation
  • Protein palmitoylation
  • Protein ubiquitination
  • TBC1D3

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