TY - JOUR
T1 - Reduced microtubule-nucleation activity of tau after dephosphorylation
AU - Morita-Fujimura, Yuiko
AU - Kurachi, Masashi
AU - Tashiro, Hideo
AU - Komiya, Yoshiaki
AU - Tashiro, Tomoko
N1 - Funding Information:
We are grateful to Professor E. Miyamoto and Dr. H. Yamamoto (Kumamoto University, School of Medicine) for the gifts of anti-phosphopeptide antibodies PP1 and PP2. This work is supported in part by a Grant-in-aid for Scientific Research from the Ministry of Education, Science, Sports and Culture, Japan, to Y.K. and T.T.
PY - 1996/8/14
Y1 - 1996/8/14
N2 - 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.
AB - 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.
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U2 - 10.1006/bbrc.1996.1195
DO - 10.1006/bbrc.1996.1195
M3 - Article
C2 - 8753784
AN - SCOPUS:0030583252
VL - 225
SP - 462
EP - 468
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 2
ER -