Table 3.

Complement of Activation Components of Phototransduction in Different Vertebrate Photoreceptors.

Photoreceptor Type	Opsin	GNAT	PDE6 Catalytic	PDE6 Inhibitory	CNGA	CNGB	Reference
Eptatretus cirrhatus	Rh1	1	X	G	X	?	This study
Mordacia mordax	LWS	X	C	H	X	X	This study
Geotria australis rod-like	Rh1	1	X	G	X	Y?	This study; see table 4
G. australis cone-like	LWS, SWS1, or SWS2	X	C	H	X	X?	This study; see table 4
Petromyzon marinus short rod-like	Rh1	1	X	G	–	–	Muradov et al. (2007, 2008)
P. marinus long cone-like	LWS	X	X	H	–	–	Muradov et al. (2007, 2008)
Gnathostome rod	Rh1	1	A and B	G	1	1	Numerous
Gnathostome cone	LWS, SWS1, Rh2, SWS2	2	C	H	3	3	Numerous
Gecko “rod-like cone”	LWS (and Rh2?)	2	C	H	3	3	Zhang et al. (2006)
Salamander “green” rod	SWS2	1	–	–	–	–	Ma et al. (2001)
Salamander blue-sensitive cone	SWS2	2	–	–	–	–	Ma et al. (2001)

Note.—The letters and numbers in columns 3–7 denote the suffix to the relevant gene name; thus, in the GNAT column, “1” denotes “GNAT1”.

–, indicates not reported;

?, indicates uncertain.

Note that this classification of PDE6 inhibitory subunits is in terms of the conventional PDE6G and PDE6H, and does not take account of the recently found PDE6I (see Text).