Membrane Antibodies

Cell membranes are also known as plasma membranes. Their structure surrounds every living cell and holds its contents inside. On the surface of membranes, there are antigens and proteins that are available for antibodies to bind against. Membranes can be permeable or semi-permeable which allows the flow of nutrients, fluids, wastes, and chemical messengers to be transported into and/ or out of the cell. In cells with nuclei, there is an internal nuclear membrane that is very similar in structure to the external cell membrane. Membranes are made of phospholipids, proteins and carbohydrates. The main structure is that of two phospholipid molecules arranged in separate layers with their fatty acid chains pointing towards each other creating a hydrophobic interior sandwiched between two hydrophilic phosphate layers. This is called the phospholipid bilayer. Secondary proteins form channels between the bilayer or peripheral surface proteins on the inner or outer membrane surface. Carbohydrates bind to these proteins in eukaryotic cell membranes forming even more complicated structures of most antigens. Membrane antibodies play integral roles in binding those antigens that facilitate or inhibit cellular membrane functions such as lipid diffusion, osmosis, passive and active transport, and vesicle formation.

Clathrin is a protein on the cell membrane that is involved in the invagination process or endocytosis or the process of a cell engulfing particles. This protein forms the surface of the actual pocket during endocytosis. The anti-clathrin antibody binds to this protein. Frizzled 8 is a member of the frizzled protein family which are signaling proteins forming transmembrane receptors. Frizzled 8 is highly expressed in human cancer of the brain, heart, kidney, pancreas, and certain skeletal muscles. Anti- frizzled 8 antibody binds to this protein and changes its formula for action.