Elevated levels of microtubule destabilizing factors in a Taxol-resistant/dependent A549 cell line with an α-tubulin mutation

Laura A. Martello, Pascal Verdier-Pinard, Heng Jia Shen, Lifeng He, Keila Torres, George A. Orr, Susan Band Horwitz

Research output: Contribution to journalArticle

132 Scopus citations

Abstract

The A549 Taxol-resistant cell lines, A549-T12 and A549-T24, were isolated in our laboratory, and are dependent on Taxol for normal growth. The microtubules in these cells displayed increased dynamicity in the absence of Taxol. In the present study, a heterozygous point mutation in Kα1-tubulin was discovered at α379 (Ser to Ser/Arg). Although Taxol binds to β-tubulin in the microtubule, sequencing of β-tubulin class I did not reveal any mutations. The expression of the α-tubulin mutation was demonstrated using high-resolution isoelectric focusing and two-dimensional gel analysis. Both the wild-type and mutant tubulin were expressed in the Taxol-resistant cell lines. The region of α-tubulin that encompasses α379 is near the COOH terminus that has been proposed as a site of interaction with microtubule-associated protein (MAP) 4 and stathmin, a tubulin-interacting protein. In the Taxol-resistant cells, the active non-phosphorylated form of stathmin was increased ∼2-fold, whereas the inactive phosphorylated forms were barely detected. The inactive phosphorylated forms of MAP4 were increased in the A549-T12 and A549-T24 cell lines. We hypothesize that these changes in tubulin/MAPs that result in increased microtubule instability may be related to the ∩-tubulin mutation and are compensated for by the stabilizing properties of Taxol.

Original languageEnglish (US)
Pages (from-to)1207-1213
Number of pages7
JournalCancer Research
Volume63
Issue number6
Publication statusPublished - Mar 15 2003

    Fingerprint

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

Martello, L. A., Verdier-Pinard, P., Shen, H. J., He, L., Torres, K., Orr, G. A., & Horwitz, S. B. (2003). Elevated levels of microtubule destabilizing factors in a Taxol-resistant/dependent A549 cell line with an α-tubulin mutation. Cancer Research, 63(6), 1207-1213.