Osmotically induced electrical signals from actin filaments

Biophys J. 1991 Jun;59(6):1284-9. doi: 10.1016/S0006-3495(91)82343-8.


Actin filaments, F-actin, a major component of the cortical cytoskeleton, play an important role in a variety of cell functions. In this report we have assessed the role of osmotic stress on the electrochemical properties of F-actin. The spontaneous Donnan potential of a polymerized actin solution (5 mg/ml) was -3.93 +/- 1.84 mV, which was linearly reduced by osmotic stress on the order of 1-20 mOsm (0.28 +/- 0.06 mV/mM). Calculated surface charge density was reduced and eventually reversed by increasing the osmotic stress as expected for a phase transition behavior. The electro-osmotic behavior of F-actin disappeared at pH 5.5 and was dependent on its filamentous nature. Furthermore, osmotically stressed F-actin displayed a nonlinear electric response upon application of electric fields on the order of 500-2,000 V/cm. These data indicate that F-actin in solution may display nonideal electro-osmotic properties consistent with ionic "cable" behavior which may be of biological significance in the processing and conduction of electrical signals within the cellular compartment.

Publication types

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

MeSH terms

  • Actins / chemistry*
  • Animals
  • Biophysical Phenomena
  • Biophysics
  • Electricity
  • Electrochemistry
  • In Vitro Techniques
  • Membrane Potentials
  • Osmotic Pressure
  • Rabbits
  • Solutions


  • Actins
  • Solutions