A fibrogranular material on the cytoplasmic face of the cell membrane of Wistar rat liver cells adapted to established culture

: A fibrogranular material associated with the inner surface of the plasma membrane of adult Rat liver cells in long-term culture is described and studied. The electrophoretic pattern of the membrane indicates that this structure might contain actin. The filamentous material had not been observed in electron microscope preparations of cell surface membranes isolated from adult Rat liver.