Nomenclature	PDE4A	PDE4B	PDE4C	PDE4D
Other names	PDE IV	PDE IV	PDE IV	PDE IV
Ensembl ID	ENSG00000065989	ENSG00000184588	ENSG00000105650	ENSG00000113448
Rank order of affinity	cAMP >> cGMP	cAMP >> cGMP	cAMP >> cGMP	cAMP >> cGMP
Activators	–	–	–	PKA-mediated phosphorylation (Houslay and Adams, 2003)
Selective inhibitors	Rolipram (9.0, Wang et al., 1997), YM976 (8.3, Aoki et al., 2000), Ro201724 (6.5, Wang et al., 1997)	Rolipram (9.0, Wang et al., 1997), Ro201724 (6.4, Wang et al., 1997)	Rolipram (6.5, Wang et al., 1997), Ro201724 (5.4, Wang et al., 1997)	Rolipram (7.2, Wang et al., 1997), Ro201724 (6.2, Wang et al., 1997)