Repeat motifs of tau bind to the insides of microtubules in the absence of taxol

被引:261
作者
Kar, S [1 ]
Fan, J [1 ]
Smith, MJ [1 ]
Goedert, M [1 ]
Amos, LA [1 ]
机构
[1] MRC, Mol Biol Lab, Cambridge CB2 2QH, England
基金
英国医学研究理事会;
关键词
kinesin; microtubule-associated proteins (MAPs); taxol; three-dimensional image reconstruction; tubulin;
D O I
10.1093/emboj/cdg001
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The tau family of microtubule-asssociated proteins has a microtubule-binding domain which includes three or four conserved sequence repeats. Pelleting assays show that when tubulin and tau are co-assembled into microtubules, the presence of taxol reduces the amount of tau incorporated. In the absence of taxol, strong binding sites for tau are filled by one repeat motif per tubulin dimer; additional tau molecules bind more weakly. We have labelled a repeat motif with nanogold and used three-dimensional electron cryomicroscopy to compare images of microtubules assembled with labelled or unlabelled tau. With kinesin motor domains bound to the microtubule outer surface to distinguish between alpha- and beta-tubulin, we show that the gold label lies on the inner surface close to the taxol binding site on beta-tubulin. Loops within the repeat motifs of tau have sequence similarity to an extended loop which occupies a site in alpha-tubulin equivalent to the taxol-binding pocket in beta-tubulin. We propose that loops in bound tau stabilize microtubules in a similar way to taxol, although with lower affinity so that assembly is reversible.
引用
收藏
页码:70 / 77
页数:8
相关论文
共 36 条
[1]   Nonsaturable binding indicates clustering of Tau on the microtubule surface in a paired helical filament-like conformation [J].
Ackmann, M ;
Wiech, H ;
Mandelkow, E .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (39) :30335-30343
[2]   MAP2 and tau bind longitudinally along the outer ridges of microtubule protofilaments [J].
Al-Bassam, J ;
Ozer, RS ;
Safer, D ;
Halpain, S ;
Milligan, RA .
JOURNAL OF CELL BIOLOGY, 2002, 157 (07) :1187-1196
[3]   The structure of microtubule-motor complexes [J].
Amos, LA ;
Hirose, K .
CURRENT OPINION IN CELL BIOLOGY, 1997, 9 (01) :4-11
[4]   Focusing-in on microtubules [J].
Amos, LA .
CURRENT OPINION IN STRUCTURAL BIOLOGY, 2000, 10 (02) :236-241
[5]   How Taxol® stabilises microtubule structure [J].
Amos, LA ;
Löwe, J .
CHEMISTRY & BIOLOGY, 1999, 6 (03) :R65-R69
[6]   INHIBITION OF TUBULIN ASSEMBLY BY RNA AND OTHER POLYANIONS - EVIDENCE FOR A REQUIRED PROTEIN [J].
BRYAN, J ;
NAGLE, BW ;
DOENGES, KH .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1975, 72 (09) :3570-3574
[7]   The microtubule-associated protein tau cross-links to two distinct sites on each α and β tubulin monomer via separate domains [J].
Chau, MF ;
Radeke, MJ ;
de Inés, C ;
Barasoain, I ;
Kohlstaedt, LA ;
Feinstein, SC .
BIOCHEMISTRY, 1998, 37 (51) :17692-17703
[8]   MRC image processing programs [J].
Crowther, RA ;
Henderson, R ;
Smith, JM .
JOURNAL OF STRUCTURAL BIOLOGY, 1996, 116 (01) :9-16
[9]  
DYE RB, 1993, J BIOL CHEM, V268, P6847
[10]   Domains of neuronal microtubule-associated proteins and flexural rigidity of microtubules [J].
Felgner, H ;
Frank, R ;
Biernat, J ;
Mandelkow, EM ;
Mandelkow, E ;
Ludin, B ;
Matus, A ;
Schliwa, M .
JOURNAL OF CELL BIOLOGY, 1997, 138 (05) :1067-1075