Cyclic nucleotide phosphodiesterase with specificity for the second messengers cAMP and cGMP, which are key regulators of many important physiological processes. Has also activity toward cUMP. Independently of its catalytic activity it is part of an E2/17beta-estradiol-induced pro-apoptotic signaling pathway. E2 stabilizes the PDE3A/SLFN12 complex in the cytosol, promoting the dephosphorylation of SLFN12 and activating its pro-apoptotic ribosomal RNA/rRNA ribonuclease activity. This apoptotic pathway might be relevant in tissues with high concentration of E2 and be for instance involved in placenta remodeling. a nucleoside 3',5'-cyclic phosphate + H2O = a nucleoside 5'-phosphate + H(+) 3',5'-cyclic AMP + H2O = AMP + H(+) 3',5'-cyclic GMP + H2O = GMP + H(+) 3',5'-cyclic UMP + H2O = H(+) + UMP Binds 2 divalent metal cations per subunit. Binds 2 divalent metal cations per subunit. Homodimer. Interacts with PDE3A; direct low affinity interaction which is stimulated by binding of 17beta-estradiol/E2 to PDE3A and that positively regulates the ribonuclease activity of SLFN12. Belongs to the cyclic nucleotide phosphodiesterase family. PDE3 subfamily.