Studies on Membrane Fusion with Natural and Model Membranes

TLDR: Exocytotic discharge is basic to the processes of cell excretion and secretion and is involved in the release of a wide variety of enzymes, hormones, and neurotransmitter substances from such cells as the newly fertilized egg, blood platelets, leukocytes, mast cells, nerve cells, and hormone-producing cells in the adrenal medulla.

Abstract: Fusion of membranes is a common and highly important event in the biology of eukaryotic cells Membrane fusion is required for the uptake by endocytosis and the intracellular digestion of extracellular material and also for the transport of intracellular materials to the extracellular space by exocytosis The formation of endocytotic vesicles at the cell surface involves invagination of a segment of the plasma membrane, which must then fuse with itself in order to form a closed vesicle Subsequently, the digestion of the contents of the endocytotic vesicles involves a series of membrane fusion sequences between these vesicles and lysosomes and Golgi vesicles (review, Edelson and Cohn, 1978) Membrane fusion also plays a prominent role in the reverse process of exocytosis in which fusion takes place at the cell surface between the membrane of the exocytotic vesicle and the plasma membrane Exocytotic discharge is basic to the processes of cell excretion and secretion and is involved in the release of a wide variety of enzymes, hormones, and neurotransmitter substances from such cells as the newly fertilized egg, blood platelets, leukocytes, mast cells, nerve cells, cells participating in the formation of kinins, angiotensin, and erythropoietin, and hormone-producing cells in the adrenal medulla, neurohypophysis, anterior pituitary, thyroid, and pancreas (reviews, Ceccarelli et al, 1974; Douglas, 1975; Carafoli et al, 1975)