Figure 1

Diagram of NPR2 showing the seven serine and threonine phosphorylation sites that were changed to glutamate (E) in the Npr2 -7E mouse. The functional domains of the homodimeric transmembrane protein NPR2 are shown in gray. Binding of CNP (green) to the extracellular domain and phosphorylation of seven serine and threonine sites (red) is required for CNP-dependent activation of the guanylyl cyclase activity of NPR2. Dephosphorylation of these regulatory sites results in a decrease in guanylyl cyclase activity; the 7E mutation results in a protein that cannot be dephosphorylated.