Table 1.

Signaling of heterotrimeric G-proteins and their modulating toxins

Subfamily	Gα	Signalinga	Modulating toxin	Toxin effect on Gα	Referencesb
Gi subfamily	Gi1	↓AC	PT	Inhibition	(a) (b)
	Gi2	↓AC	PT	Inhibition	(a) (b)
	Gi3	↓AC	PT	Inhibition	(a) (b)
	Go	↓Ca2+ channels	PT	Inhibition	(a) (b)
	Gt	↑cGMP-PDE	PT	Inhibition	(a) (b) (c)
			CT	Activation	(a) (b) (d)
	Ggust	↑PDE	PT	?	(e)
	Gz	↓AC	?	?	(f) (g)
Gs subfamily	Gs	↑AC	CT	Activation	(a) (b)
	Golf	↑AC	CT	Activation	(h)
Gq subfamily	Gq	↑PLCβ, ↑Rho	PMT	Activation/Inhibitionc	(i) (j) (k)
	G11	↑PLCβ, ↑Rho	?	?	(k)
	G14	↑PLCβ	?	?
	G15	↑PLCβ	?	?
	G16	↑PLCβ	?	?
G12 subfamily	G12	↑Rho	?	?
	G13	↑Rho	?	?

^aAC: adenylate cyclase; PDE: phosphodiesterase; PLC: phopholipase C

^b(a) (Fields and Casey 1997), (b) (Casey and Gilman 1988), (c) (Van Dop et al. 1984a), (d) (Van Dop et al. 1984b), (e) (Gilbertson et al. 2000), (f) (Casey et al. 1990), (g) (Ho and Wong 2001), (h) (Jones et al. 1990), (i) (Wilson et al. 1997), (j) (Zywietz et al. 2001), (k) (Vogt et al. 2003)

^cInitial activation, followed by uncoupling of G_q signaling. Prolonged treatment with PMT results in inhibition