Table 11-1 Some Examples of Plasma Membrane Proteins and Their Functions Functional Class Protein Example Specific Function Transporters Na'pump actively pumps Na'out of cells and K'in Linkers integrins link intracellular actin filaments to extracellular matrix proteins Receptors platelet-derived binds extracellular PDGF and,as a growth factor consequence,generates intra- (PDGF)receptor cellular signals that cause the cell to grow and divide Enzymes adenvlate cyclase catalyzes the production of intra- cellular cyclic AMP in response to extracellular signals