Fast cell membrane displacements in B lymphocytes. Modulation by dihydrocytochalasin B and colchicine

A novel type of cell membrane movement was characterized in B lymphocytes. Local submicron cell membrane displacements, within the frequency range 0.3-15 Hz, were registered in a murine lymphoma B cell line by a novel optical method based on point dark field microscopy. The cell membrane displacements were measured by monitoring changes in light scattering from very small illuminated areas (0.25 microns2) at the edge of the cell surface. B lymphocytes manifest a relative change in light scattering of 7.7 +/- 1.3% (mean +/- SD) which corresponds to cell membrane transverse displacement of 131 +/- 22 nm. The confinement of cell membrane displacements to microdomains (less than or equal to 0.2 microns2) emerged from the observed dependence of the displacement amplitude on the area size from which it is monitored. Colchicine (1 microM) decreased membrane fluctuations down to a value of 88 +/- 14 nm, whereas dihydrocytochalasin B (2 microM) increased the amplitude of membrane displacements up to 184 +/- 31 nm. These findings demonstrate the existence of a dynamic mechanical interaction between the cytoskeleton and the cell membrane in the frequency range of 0.3-15 Hz. The modulation of these interactions by the disruption of microfilaments or or microtubules is explained in terms of the induced strain changes imposed on the cell membrane.