Cis‐ and trans‐ membrane control of cell surface topography

The topographic distributions of cell surface components can be modified by perturbations from the cell membrane exterior (cis‐membrane effect) or by perturbations from the cell interior that are transferred across the membrane (trans‐membrane effect). Using the human erythrocyte ghost as a model system, cis‐membrane effects on the topography of anionic sites were produced in B+ ghosts with anti‐B sera (but not with anti‐A), R. communis agglutinin and concanavalin A (but not with D. biflorus agglutinin). Cis‐membrane linkage was monitored by the state of aggregation of membrane‐bound colloidal iron hydroxide particles which bind almost exclusively to neuraminidase‐sensitive N‐acetylneuraminic acid residues on the outer surface. Trans‐membrane effects were observed when purified antibodies against an inner surface membrane protein, spectrin, were sequestered inside the ghosts. The sequestered antispectrin bound to spectrin at inner membrane surface and caused aggregation of the anionic sites on the outer membrane surface. The trans‐membrane effects of antispectrin required intact γG antibodies (Fab would not substitute) and was time‐ and concentration‐dependent.