The yeast class V myosins, Myo2p and Myo4p, are nonprocessive actin-based motors

J Cell Biol. 2001 May 28;153(5):1121-6. doi: 10.1083/jcb.153.5.1121.

Abstract

The motor properties of the two yeast class V myosins, Myo2p and Myo4p, were examined using in vitro motility assays. Both myosins are active motors with maximum velocities of 4.5 microm/s for Myo2p and 1.1 microm/s for Myo4p. Myo2p motility is Ca(2+) insensitive. Both myosins have properties of a nonprocessive motor, unlike chick myosin-Va (M5a), which behaves as a processive motor when assayed under identical conditions. Additional support for the idea that Myo2p is a nonprocessive motor comes from actin cosedimentation assays, which show that Myo2p has a low affinity for F-actin in the presence of ATP and Ca(2+), unlike chick brain M5a. These studies suggest that if Myo2p functions in organelle transport, at least five molecules of Myo2p must be present per organelle to promote directed movement.

Publication types

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

MeSH terms

  • Actins / metabolism*
  • Adenosine Triphosphate / metabolism
  • Adenosine Triphosphate / pharmacology
  • Animals
  • Antibodies / immunology
  • Brain
  • Calcium / pharmacology
  • Calmodulin-Binding Proteins / immunology
  • Calmodulin-Binding Proteins / metabolism
  • Carrier Proteins / metabolism*
  • Chickens
  • Fungal Proteins / metabolism*
  • Kinetics
  • Microscopy, Video
  • Molecular Motor Proteins / immunology
  • Molecular Motor Proteins / metabolism*
  • Movement / drug effects
  • Myosin Heavy Chains*
  • Myosin Type II*
  • Myosin Type V*
  • Myosins / metabolism*
  • Nerve Tissue Proteins / immunology
  • Nerve Tissue Proteins / metabolism
  • Protein Binding / drug effects
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • Schizosaccharomyces pombe Proteins*

Substances

  • Actins
  • Antibodies
  • Calmodulin-Binding Proteins
  • Carrier Proteins
  • Fungal Proteins
  • MYO2 protein, S cerevisiae
  • MYO2 protein, S pombe
  • Molecular Motor Proteins
  • Myo4 protein, S cerevisiae
  • Nerve Tissue Proteins
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces pombe Proteins
  • chicken brain myosin-V p190
  • Adenosine Triphosphate
  • Myosin Type II
  • Myosin Type V
  • Myosin Heavy Chains
  • Myosins
  • Calcium