Microtubule-associated proteins and microtubule-based translocators have different binding sites on tubulin molecule

V. I. Rodionov, F. K. Gyoeva, A. S. Kashina, S. A. Kuznetsov, V. I. Gelfand

Research output: Contribution to journalArticle

67 Scopus citations

Abstract

It has been previously shown that a class of microtubule proteins, the so-called microtubule-associated proteins (MAPs), binds to the C-terminal part of tubulin subunits. We show here that microtubules composed of tubulin whose 4-kDa C-terminal domain was cleaved by subtilisin (S-microtubules) are unable to bind MAPs but can still bind the anterograde translocator protein kinesin and the retrograde translocator dynein. Binding of both motors to S-microtubules, like their binding to normal microtubules, was ATP-dependent. In addition, direct competition experiments showed that binding sites for kinesin and MAPs on the microtubule surface lattice do not overlap. Furthermore, S-microtubules stimulated the ATPase activity of kinesin at least 8-fold, and the affinities of kinesin for control and S-microtubules were identical. S-microtubules were able to glide along kinesin-coated coverslips at a rate of 0.2 μm/s, the same rate as control microtubules. We conclude, that unlike MAPs, kinesin and cytoplasmic dynein bind to the tubulin molecule outside the C-terminal region.

Original languageEnglish (US)
Pages (from-to)5702-5707
Number of pages6
JournalJournal of Biological Chemistry
Volume265
Issue number10
StatePublished - Apr 25 1990

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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