ABSTRACT
This chapter discusses the possible involvement of membrane proteins in fusion and attempts to indicate how proteins might act that the general requirements for fusion are met under the conditions of membrane fusion during exocytosis. Fusion of biological membranes in general, and exocytotic membrane fusion in particular, occurs in a highly specific fashion. The chapter also discusses the interaction between phospholipid vesicles. Phospholipid vesicle systems have proven to be of great value in the study of the interactions between lipid bilayer membranes. There are extensive data, however, on interbilayer forces, derived from studies on the interaction between lipid membranes in stacked multibilayer systems and lipid bilayers adsorbed onto a hydrophilic surface. When phospholipid bilayers are forced to close approach strong repulsive hydration forces arise, which are due to the work involved in removal of the water that is tightly bound to the phospholipid headgroups.
