Table 1

Regulators of adenylyl cyclases

Class	Regulators	Cyclases	Effects	Conditions	Sites	References
G_s/G_i	G_sα	All	+		High affinity: C_1a (amino terminus), C_2a (α2, α3/β4)	Yan et al., 1997a; Tesmer et al., 1997)
					Low affinity: ACVI-C_1b	Chen et al., 1997
	G_βγ	I	−	CaM > G_sα >> forskolin	Unknown	Tang and Gilman, 1991
		II, IV, VII	+	G_sα >> forskolin	C_2a (α3)	Tang and Gilman, 1991; Gao and Gilman, 1991; Yoshimura et al., 1996; Chen et al. 1995
	G_iα	I, V, VI	−		Unknown	Taussig et al, 1994
	G_oα	I	−	CaM >> forskolin > G_sα	Unknown	Taussig et al., 1994
	G_zα	I, V	−		Unknown	Kozasa and Gilman, 1995
Small chemicals	Forskolin	All except IX	+	G_sα synergy	C₁/C₂interface	Zhang et al., 1997b; Tesmer et al.1997; Yan et al., 1998
	Adenosine	All	−	Enhanced by PPi	C₁/C₂ interface, cAMP competitor	Tesmeret al. 1997; Liu et al., 1997
Feedback inhibition	PKA	V, VI	−	G_sα, forskolin	Ser674 (ACVI)	Iwami et al., 1995; Chen et al., 1997
Ca²⁺/G_q	Ca²⁺/CaM	I, VIII	+		ACI-C_1b (495–522), ACIII, VIII–unknown	Tang et al.; Cali et al., 1994;Vorherr et al., 1993; Wu et al., 1993
	PKC	II, V, VII	+		ACII (1034-1068, Thr 1057)	Kawabe et al., 1994; Jacobowitz and Iyengar, 1994;Yoshimura et al. 1993; Zimmermann and Taussig, 1996; Levin and Reed, 1995; Bol et al. 1997
		VI	−		Unknown	Lai et al. 1997
	Ca²⁺ ^1-a	V, VI	−		C_1b ^1-b	Yoshimura and Cooper, 1992;Scholich et al. 1997
	CaM kinase^1-a	III	−			Wei et al., 1996
	PP2B^1-a	IX	−			Antoni et al., 1995

↵1-a Direct modulation of adenylyl cyclases remains to be determined.
↵1-b There are high and low affinity sites and C_1b is likely to be the low affinity site, which is common among adenylyl cyclases.