The kinesin-related protein MCAK is a microtubule depolymerase that forms an ATP-hydrolyzing complex at microtubule ends

Mol Cell. 2003 Feb;11(2):445-57. doi: 10.1016/s1097-2765(03)00049-2.

Abstract

MCAK belongs to the Kin I subfamily of kinesin-related proteins, a unique group of motor proteins that are not motile but instead destabilize microtubules. We show that MCAK is an ATPase that catalytically depolymerizes microtubules by accelerating, 100-fold, the rate of dissociation of tubulin from microtubule ends. MCAK has one high-affinity binding site per protofilament end, which, when occupied, has both the depolymerase and ATPase activities. MCAK targets protofilament ends very rapidly (on-rate 54 micro M(-1).s(-1)), perhaps by diffusion along the microtubule lattice, and, once there, removes approximately 20 tubulin dimers at a rate of 1 s(-1). We propose that up to 14 MCAK dimers assemble at the end of a microtubule to form an ATP-hydrolyzing complex that processively depolymerizes the microtubule.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Animals
  • Binding Sites
  • Hydrolysis
  • In Vitro Techniques
  • Kinesin / chemistry
  • Kinesin / metabolism*
  • Kinetics
  • Microtubules / metabolism*
  • Models, Biological
  • Osmolar Concentration
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Tubulin / chemistry
  • Tubulin / metabolism

Substances

  • KIF2C protein, human
  • Recombinant Proteins
  • Tubulin
  • Adenosine Triphosphate
  • Kinesin