Kinesin's light chains inhibit the head- and microtubule-binding activity of its tail

Yao Liang Wong, Sarah E. Rice

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Kinesin-1 is a microtubule-based motor comprising two heavy chains (KHCs) and two light chains (KLCs). Motor activity is precisely regulated to avoid futile ATP consumption and to ensure proper intracellular localization of kinesin-1 and its cargoes. The KHC tail inhibits ATPase activity by interacting with the enzymatic KHC heads, and the tail also binds microtubules. Here, we present a role for the KLCs in regulating both the head- and microtubule-binding activities of the kinesin-1 tail. We show that KLCs reduce the affinity of the head-tail interaction over tenfold and concomitantly repress the tail's regulatory activity. We also show that KLCs inhibit tail-microtubule binding by a separate mechanism. Inhibition of head-tail binding requires steric and electrostatic factors. Inhibition of tail-microtubule binding is largely electrostatic, pH dependent, and mediated partly by a highly negatively charged linker region between the KHC-interacting and cargo-binding domains of the KLCs. Our data support a model wherein KLCs promote activation of kinesin-1 for cargo transport by simultaneously suppressing tail-head and tail-microtubule interactions. KLC-mediated inhibition of tail-microtubule binding may also influence diffusional movement of kinesin-1 on microtubules, and kinesin-1's role in microtubule transport/sliding.

Original languageEnglish (US)
Pages (from-to)11781-11786
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume107
Issue number26
DOIs
StatePublished - Jun 29 2010

Keywords

  • Fluorescence anisotropy
  • Molecular motor
  • Regulation

ASJC Scopus subject areas

  • General

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