Table 2.

5-HT₂ receptor transmembrane region (TMR) amino acids with known functions

TMR	Position in receptor	Function	Conserved	References
TM1	2CHum55W	LB	No	Roth et al. (1997a,b)
TM2	2CHum104L	LB	No	Wang et al. (1993), Choudhary et al. (1995), Sealfon et al. (1995), Roth et al. (1997b), Manivet et al. (2002)
	2CHum111L	LB	No
	2CHum113A	LB	No
	2βPan118D	LB and G-protein coupling, binds to residue	Yes
		2BPan697N in TM7
TM3	2βPan152D	LB and membrane targeting	Yes	Kristiansen et al. (2000), Visiers et al. (2001), Kroeze et al. (2002), Manivet et al. (2002), Shapiro et al. (2002), present study
	2CHum138S	LB	No
	2βPan169D	Activation (see text)	Yes
	2βPan170R	Activation (see text)	Yes
	2βPan171F	Activation (see text)	No
TM5	2βPan236S	LB	Yes	Almaula et al. (1996a,b), Johnson et al. (1997), Shapiro et al. (2000), Manivet et al. (2002)
	2βPan240F	LB contributes to HBP	Yes
	2βPan242I	LB	Yes
	2CHum222A	LB	No
	2CHum224F	LB	No
	2CHum228T	LB	No
TM6	2CHum305N	Activation	No	Choudhary et al. (1993, 1995); Roth et al. (1997a,b), Shapiro et al. (2000), Visiers et al. (2001), Manivet et al. (2002)
	2CHum310S	Activation	No
	2βPan644E	Activation (see text)	Yes
	2βPan645Q	Activation	Yes
	2βPan646K	Activation (see text)	Yes
	2βPan650V	Activation	Yes
	2βPan651L	Activation	Yes
	2βPan654V	Activation	Yes
	2βPan662W	LB contributes to HBP	Yes
	2βPan664P	Activation: hinge allowing TM3/TM6 association—disassociation	Yes
	2βPan665F	LB contributes to HBP	Yes
	2βPan666F	LB contributes to HBP	Yes
	2βPan669N	LB	Yes
TM7	2βPan688W	LB contributes to HBP	Yes	Sealfon et al. (1995), Roth et al. (1997a,b), Rosendorff et al. (2000), Manivet et al. (2002)
	2βPan691Y	LB contributes to HBP	Yes
	2CHum353F	LB	No
	2βPan697N	LB/coupling: interacts with 2Bpan118D	Yes
	2βPan701Y	Activation	Yes

LB, Ligand binding; HBP, hydrophobic binding pocket.