Reduced microtubule-nucleation activity of tau after dephosphorylation

Yuiko Morita-Fujimura, Masashi Kurachi, Hideo Tashiro, Yoshiaki Komiya, Tomoko Tashiro

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Based on video-enhanced differential interference contrast (DIC) microscopy, we developed a small-scale method which is capable of measuring both the lengths and the number densities of microtubules (MTs) assembled in vitro. With this method, effect of dephosphorylation on the activity of bovine brain tau protein to promote the assembly of tubulin at physiological concentration (15 μM) was quantitatively analyzed. The MT number density was selectively reduced when tau isolated directly in the presence of phosphatase inhibitors (N-tau) was dephosphorylated in vitro (DP-tau), without significant changes in the mean MT length or the binding affinity toward preformed MTs. Tau obtained from brain MTs (MT-tau) also exhibited lower nucleation activity in spite of its high MT-binding affinity. The results indicate that nucleation, elongation and MT-binding are distinct aspects of tau function which are differentially affected by the phosphorylation state of tau.

Original languageEnglish
Pages (from-to)462-468
Number of pages7
JournalBiochemical and biophysical research communications
Volume225
Issue number2
DOIs
Publication statusPublished - 1996 Aug 14

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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