Red cell comets: ultrastructure of axial elongation of the membrane skeleton

In order to study intact red cell membrane skeletons, we developed two methods for the electron microscopic study of stress-ruptured and partially opened glutaraldehyde pre-fixed Triton shells of red cell ghosts. Both methods showed continuous networks of fine filaments decorated and apparently crosslinked by elongated particles. Our electron micrographs show a filamentous component that is morphologically consistent with F-actin. Quantitative considerations, including the dimensions of the elongated particles and published estimates of the number of particles in situ, suggest that compact spectrin decamers or dodecamers may exist in intact red cells. Long filaments consistent with F-actin appear to be decorated with the putative spectrin particles.