Role of phosphatidylinositol(4,5)bisphosphate organization in membrane transport by the Unc104 kinesin motor

Cell. 2002 May 3;109(3):347-58. doi: 10.1016/s0092-8674(02)00708-0.

Abstract

Unc104 (KIF1A) kinesin transports membrane vesicles along microtubules in lower and higher eukaryotes. Using an in vitro motility assay, we show that Unc104 uses a lipid binding pleckstrin homology (PH) domain to dock onto membrane cargo. Through its PH domain, Unc104 can transport phosphatidylinositol(4,5)bisphosphate (PtdIns(4,5)P2)-containing liposomes with similar properties to native vesicles. Interestingly, liposome movement by monomeric Unc104 motors shows a very steep dependence on PtdIns(4,5)P2 concentration (Hill coefficient of approximately 20), even though liposome binding is noncooperative. This switch-like transition for movement can be shifted to lower PtdIns(4,5)P2 concentrations by the addition of cholesterol/sphingomyelin or GM1 ganglioside/cholera toxin, conditions that produce raft-like behavior of Unc104 bound to lipid bilayers. These studies suggest that clustering of Unc104 in PtdIns(4,5)P2-containing rafts provides a trigger for membrane transport.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Biological Transport
  • Blood Proteins / chemistry
  • Blood Proteins / metabolism
  • Caenorhabditis elegans / genetics
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Membrane / physiology*
  • Dictyostelium
  • Dose-Response Relationship, Drug
  • In Vitro Techniques
  • Kinesins / isolation & purification
  • Kinesins / metabolism*
  • Lipid Bilayers / metabolism
  • Liposomes / metabolism
  • Membrane Microdomains / metabolism
  • Microtubules / physiology
  • Models, Biological
  • Nerve Tissue Proteins / isolation & purification
  • Nerve Tissue Proteins / metabolism*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism
  • Phosphatidylinositol 4,5-Diphosphate / physiology*
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism
  • Sequence Homology, Amino Acid
  • Transport Vesicles / physiology*

Substances

  • Blood Proteins
  • Lipid Bilayers
  • Liposomes
  • Nerve Tissue Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphoproteins
  • platelet protein P47
  • Kinesins