Plasma membrane guanylate cyclase is a multimodule transduction system.

This minireview highlights the studies which suggest that guanylate cyclase is a single-component transducing system, containing distinct signaling modules in a single membrane-spanning protein. A guanylate cyclase signaling model is proposed which envisions the following sequential events: (1) a signal is initiated by the binding of the hormone to the ligand binding module; (2) the signal is potentiated by ATP at ARM; and (3) the amplified signal is finally transduced at the catalytic site. All of these signaling steps together constitute a switch, which when turned on, generates the second messenger cyclic GMP.