. 2011 Oct 25;286(52):44691–44701. doi: 10.1074/jbc.M111.303917

TABLE 1.

Summary of effect of chimeras and point mutations on a human P2X1 receptor background

Mean data are shown for peak current amplitude to a maximal concentration of ATP (usually 100 μm) as well as the time-course for the peak current to decay by 50%. For mutants that did not decay by 50% during a 20-s application of a maximal concentration of ATP, the % of peak current remaining at 20 s is given. The decline in current amplitude on washout of ATP (deactivation) is expressed as the % of the current remaining at a 50-s washout. ATP potency is given as pEC₅₀ for some mutants. n = 3–20.

Predominant P2X1 chimera/mutant	Peak current	pEC₅₀	In the presence of 100 μm ATP		Washout of ATP % remaining at 50 s washout
Predominant P2X1 chimera/mutant	Peak current	pEC₅₀	Desensitization to 50% peak	% remaining at 20 s	Washout of ATP % remaining at 50 s washout
	μA		s
P2X1	10.8 ± 1.3	6.3 ± 0.02	1.1 ± 0.13	4.8 ± 1.00	0.06 ± 0.03
2-N	8.4 ± 3.8	6.3 ± 0.13	3.7 ± 0.40^a		0.21 ± 0.08
2-Nα	6.4 ± 0.9		2.3 ± 0. 22^a
2-Nβ	13.9 ± 0.7		7.6 ± 0. 56^a
Triple (T)	9.0 ± 0.8		2.5 ± 0.29		9.2 ± 1.60
T+ 32–35	8.9 ± 0.8		4.1 ± 0.15		13.2 ± 2.65^b
T+ 36–44	10.0 ± 0.6		2.7 ± 0.07		13.9 ± 2.02^b
T+ 45–47	11.2 ± 1.5		4.0 ± 0.65		19.6 ± 0.76^a
2(D17E)	14.8 ± 0.9		1.8 ± 0.23^a		3.8 ± 3.80
2-(20–23)	6.4 ± 0.9		1.6 ± 0.20^a		11.2 ± 1.16^b
2-(27–29)	4.8 ± 0.7		0.8 ± 0.06^b		0.4 ± 0.28
2-(D17E) + 20–23	6.6 ± 0.1		1.9 ± 0.24^a		7.6 ± 1.24
2-(D17E) + 27–29	7.0 ± 1.2		3.8 ± 0.14^a		0.5 ± 0.13
2-(20–23) + (27–29)	11.8 ± 1.2		3.5 ± 0.73^a		5.9 ± 0.54
2-TM1	11.5 ± 2.3	7.3 ± 0.09^a		78.1 ± 8.50^a	41.8 ± 2.80^a
2-EXT	3.4 ± 1.1	6.5 ± 0.07^b	0.7 ± 0.03	0.9 ± 0.48	24.2 ± 0.74^a
2-TM2	5.5 ± 1.3	6.0 ± 0.09		67.5 ± 7.19^a	48.3 ± 2.80^a
2-TM1 and -2	10.0 ± 1.3	6.5 ± 0.16	0.6 ± 0.11		5.7 ± 0.69
2-C	0.1 ± 0.04^c	5.7 ± 0.14^b	0.07 ± 0.01^a,c		0.04 ± 0.04
2-Cα	1.3 ± 0.4^c		0.1 ± 0.02^a
2-Cβ	5.7 ± 0.4		0.4 ± 0.08^b
2-C(NKVYS)	6.2 ± 1.3		0.08 ± 0.02^c		0.08 ± 0.08
2-C(NKVYSH)	0.5 ± 0.1^c		0.09 ± 0.02^c		0.20 ± 0.20
2-C(TMFM)	8.0 ± 0.7		0.2 ± 0.03^b		0.21 ± 0.07
2-NC	18.6 ± 1.2^a	5.6 ± 0.14^b	4.7 ± 0.42^a		1.48 ± 0.67
2-Nβ Cα	10.5 ± 1.0		1.1 ± 0.07		5.3 ± 0.61
2-Nβ TM1	6.1 ± 1.4	7.0 ± 0.05^b		98.4 ± 0.62^a	47.9 ± 3.23^a
2-Nβ TM1 + 2	2.7 ± 0.6			90.4 ± 5.80^a	69.3 ± 2.5^a
2-(D17E) TM1 + 2	15.0 ± 1.6		9.6 ± 0.75	64.8 ± 3.60^a	43.2 ± 2.81^a
2-(20–23) TM1 + 2	4.9 ± 0.8			95.4 ± 1.40^a	69.4 ± 2.46^a
2-(21–23) TM1 + 2	8.1 ± 0.8			99.2 ± 0.28^a	93.8 ± 2.30^a
2-(27–29) TM1 + 2	12.0 ± 2.5		2.3 ± 0.28	13.0 ± 2.90^a	4.3 ± 0.67
2-TM1 + 2 Cα	3.5 ± 0.5		0.2 ± 0.64	0.9 ± 0.49^b	1.02 ± 0.38
2-Nβ TM1 + 2 Cα	4.6 ± 0.4			80.9 ± 4.40^a	59.8 ± 1.86^a
2-TM2 Cα	1.4 ± 0.3^a			92.3 ± 3.70^a	73.7 ± 5.88^a

^a p < 0.001.

^b p < 0.05.

^c p < 0.01.