Effect of charge changes in ligand-triggered membrane cooperative transitions

An analysis is given for the influence of surface charge changes due to ligand-receptor interactions in the membrane cooperative transitions. The simple case of two allosteric states accessible each to one ligand is considered using affinity constant earlier described in terms of surface properties. It is found that if indeed there are membrane cooperative effects, some decrease in charge facilitates the appearance of very “sharp” first-order transitions, even supposing that cooperativity parameter values are far above the normally critical value Λ_c = e^?4. When the charge is increased, however, phase transitions are delayed and only assume a threshold response if Λ < e^?4. It is concluded that such contact-dependent effects might be implicated in membrane control action for cell proliferation.