Dynactin functions as both a dynamic tether and brake during dynein-driven motility

Nat Commun. 2014 Sep 4;5:4807. doi: 10.1038/ncomms5807.

Abstract

Dynactin is an essential cofactor for most cellular functions of the microtubule motor cytoplasmic dynein, but the mechanism by which dynactin activates dynein remains unclear. Here we use single molecule approaches to investigate dynein regulation by the dynactin subunit p150(Glued). We investigate the formation and motility of a dynein-p150(Glued) co-complex using dual-colour total internal reflection fluorescence microscopy. p150(Glued) recruits and tethers dynein to the microtubule in a concentration-dependent manner. Single molecule imaging of motility in cell extracts demonstrates that the CAP-Gly domain of p150(Glued) decreases the detachment rate of the dynein-dynactin complex from the microtubule and also acts as a brake to slow the dynein motor. Consistent with this important role, two neurodegenerative disease-causing mutations in the CAP-Gly domain abrogate these functions in our assays. Together, these observations support a model in which dynactin enhances the initial recruitment of dynein onto microtubules and promotes the sustained engagement of dynein with its cytoskeletal track.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Binding Sites
  • COS Cells
  • Cell Movement / physiology
  • Chlorocebus aethiops
  • Dynactin Complex
  • Dyneins / antagonists & inhibitors
  • Dyneins / genetics
  • Dyneins / metabolism*
  • Dyneins / ultrastructure
  • Female
  • Humans
  • Male
  • Mice
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Microtubule-Associated Proteins / ultrastructure
  • Microtubules / metabolism
  • Microtubules / ultrastructure
  • Protein Binding
  • Protein Structure, Tertiary
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Recombinant Fusion Proteins / ultrastructure

Substances

  • DCTN1 protein, human
  • Dctn1 protein, mouse
  • Dynactin Complex
  • Microtubule-Associated Proteins
  • RNA, Small Interfering
  • Recombinant Fusion Proteins
  • Dyneins