The expanding family of guanylyl cyclases.

The guanylyl cyclase receptor family contains members that exist in both the particulate and soluble fractions of cell homogenates. Soluble forms of the enzyme recognize EDRF (nitric oxide) or similar molecules, while diversity within the extracellular domain of the plasma membrane forms has resulted in a series of guanylyl cyclases that are specifically activated by different ligands. David Garbers and colleagues describe the recent cloning of some of these molecules.