Reconstitution in vitro of the motile apparatus from the amoeboid sperm of Ascaris shows that filament assembly and bundling move membranes

Cell. 1996 Jan 12;84(1):105-14. doi: 10.1016/s0092-8674(00)80997-6.


We have developed an in vitro motility system from Ascaris sperm, unique amoeboid cells that use filament arrays composed of major sperm protein (MSP) instead of an actin-based apparatus for locomotion. Addition of ATP to sperm extracts induces formation of fibers approximately 2 microns in diameter. These fibers display the key features of the MSP cytoskeleton in vivo. Each fiber consists of a meshwork of MSP filaments and has at one end a vesicle derived from the plasma membrane at the leading edge of the cell. Fiber growth is due to filament assembly at the vesicle; thus, fiber elongation results in vesicle translocation. This in vitro system demonstrates directly that localized polymerization and bundling of filaments can move membranes and provides a powerful assay for evaluating the molecular mechanism of amoeboid cell motility.

Publication types

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

MeSH terms

  • Amoeba / cytology*
  • Amoeba / ultrastructure
  • Animals
  • Antigens, Helminth / analysis
  • Antigens, Helminth / physiology
  • Ascaris / cytology*
  • Cell Membrane / chemistry
  • Cell Membrane / physiology
  • Cell Movement / physiology*
  • Cytoskeleton / physiology
  • Cytosol / chemistry
  • Cytosol / physiology
  • Detergents
  • Helminth Proteins / physiology*
  • Intracellular Membranes / chemistry
  • Intracellular Membranes / physiology
  • Male
  • Microscopy, Electron
  • Polymers / metabolism
  • Pseudopodia / chemistry
  • Pseudopodia / physiology
  • Spermatozoa / cytology
  • Spermatozoa / ultrastructure


  • Antigens, Helminth
  • Detergents
  • Helminth Proteins
  • Polymers
  • major sperm protein, nematode