Removal of βIII Isotype Enhances Taxol Induced Microtubule Assembly

Lu Qing, Richard F. Luduena

Research output: Contribution to journalArticle

102 Scopus citations

Abstract

The interaction of βIII-depleted tubulin with taxol was investigated. A monoclonal antibody against the βIII tubulin isotype was immobilized on a sepharose 4B column and used to remove the βIII tubulin isotype from unfractionated tubulin. The assembly of βIII-depleted tubulin in the presence of taxol was enhanced compared to unfractionated tubulin. The critical concentration of unfractionated tubulin in the presence of 10 μM taxol is 0.4 mg/ml, while the critical concentration of βIII-depleted tubulin is 0.16 mg/ml. At different concentrations of taxol, the assembly of βIII-depleted tubulin is increased relative to that of unfractionated tubulin and reaches the maximum at about a 1 : 1 ratio of tubulin and taxol. The assembly of un fractionated tubulin and βIII-depleted tubulin has also been studied by electron microscopy. After 2 minutes at 37°C, unfractionated tubulin assembly in the presence of 10 μM taxol results only in ribbon-like and ring structures; there are no visible microtubules. By 5 minutes, microtubules appear and increase in length. The assembly of βIII-depleted tubulin in the presence of 10 μM taxol occurs more quickly. In contrast to the case with unfractionated tubulin, βIII-depleted tubulin assembles within 2 minutes into microtubules which increase in length with time. At 30 minutes, microtubules assembled from βIII-depleted tubulin are shorter than the microtubules assembled from unfractionated tubulin. There is no visible difference between the microtubules assembled from unfractionated tubulin and βIII-depleted tubulin. Taxol-induced βIII-depleted tubulin assembly is more resistant to the inhibiting effect of podophyllotoxin and colchicine. It is also less sensitive to the inhibiting effect of cold temperature.

Original languageEnglish (US)
Pages (from-to)173-182
Number of pages10
JournalCell Structure and Function
Volume18
Issue number3
DOIs
StatePublished - Jan 1 1993

Keywords

  • microtubule assembly
  • taxol
  • β-tubulinisotypes

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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