PDE3A is mainly implicated in cardiovascular function and fertility but PDE3B is mainly implicated in lipolysis. Table 1 is an overview of localization of the PDE3 isoforms.
In general, PDE3 can be either cytosolic or membrane-bound and has been associated to plasma membrane, sarcoplasmic reticulum, golgi, and nucleus envelope.
PDE3B is predominantly membrane-associated, and is localized to endoplasmic reticulum and microsomal fractions.
PDE3A can be either membrane-associated or cytosolic, depending on the variant and the cell type it is expressed in.