Table 1.

Regulatory properties of transmembrane adenylyl cyclase (AC) isoforms

AC isoform	G protein regulators		Protein kinases		Calcium	RGS2	Other
	stimulatory	inhibitory	stimulatory	inhibitory
Group I
AC1	Gsα	Gα i, z, o, Gβγ	PKCα (weak)	CaMK IV	↑ CaM		PAM
AC8	Gsα	Gβγ			↑ CaM		PP2A
AC3	Gsα	Gβγ	PKCα (weak)	CaMK II	↑ CaM∗	↓
Group II
AC2	Gsα, Gβγ		PKCα
AC4	Gsα, Gβγ			PKCα
AC7	Gsα, Gβγ		PKCα				PAM
Group III
AC5	Gsα, Gβγ	Gα i, z	PKC (α, ζ)	PKA	↓ free Ca2+	↓	PAM, Ric8a
AC6	Gsα, Gβγ	Gα i, z		PKA, PKC (α, ε)	↓ free Ca2+	↓	PAM, Snapin
Group IV
AC9	Gsα			PKC	↓ via calcineurin