Figure 1

Schematic organization of the PDE4 family. PDE4s have a highly conserved globular catalytic domain, flanked by regulatory domains, such as the PDE4 signature domains UCR1 and UCR2 (for Upstream Conserved Regulatory domains), containing, for example, a PKA phosphorylation site. PDE4s are divided in short or long forms, defined by the absence or the presence of UCR1. Some examples of short and long forms, expressed or regulated in human myometrium are quoted. Short form products of PDE4B and PDE4D gene derived from a cAMP-sensitive intronic promoter. Long forms are usually constitutive.