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Extracting Modified Microtubules from Mammalian Cells to Study Microtubule-Protein Complexes by Cryo-Electron Microscopy
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Proteomic characterization of cytoskeletal and mitochondrial class III beta-tubulin

Lucia Cicchillitti1, Roberta Penci, Michela Di Michele

  • 1Department of Oncology, Catholic University of the Sacred Heart, Largo A. Gemelli, 1-86100, Campobasso, Italy.

Molecular Cancer Therapeutics
|July 23, 2008
PubMed

Insights

Class III beta-tubulin (TUBB3) is linked to cancer drug resistance. Its modifications and interactions suggest it acts as a survival factor, offering new therapeutic targets.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Class III beta-tubulin (TUBB3) is an established marker for drug resistance in human cancers.
  • Understanding the precise mechanisms of TUBB3's role in drug resistance is crucial for developing novel therapeutic strategies.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying TUBB3's involvement in cancer drug resistance.
  • To identify and characterize TUBB3 isoforms and their functional roles in drug-resistant cells.

Main Methods:

  • Analysis of TUBB3 in drug-sensitive and drug-resistant cell lines using electrophoretic techniques.
  • Isoform characterization via glycosylation and phosphorylation analysis, subcellular localization studies.
  • Protein complex identification using 2D SDS-PAGE, immunoprecipitation, and mass spectrometry.

Main Results:

  • Two distinct TUBB3 isoforms were identified with different electrophoretic profiles.
  • A higher molecular weight isoform, glycosylated and phosphorylated, localized to the cytoskeleton; a lower molecular weight isoform localized to mitochondria.
  • Phosphorylation and glycosylation levels correlated with drug resistance and cytoskeletal localization.
  • TUBB3 forms protein complexes via disulfide bridges, interacting with proteins involved in oxidative stress and glucose deprivation adaptation.
  • These interacting proteins suggest TUBB3 functions as a survival factor.

Conclusions:

  • TUBB3's post-translational modifications (glycosylation, phosphorylation) and compartmentalization are associated with cancer drug resistance.
  • TUBB3 interacts with proteins that promote survival under stress, directly contributing to drug resistance.
  • Targeting TUBB3 glycosylation may inhibit its cytoskeletal function and overcome drug resistance.

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