ABCC7 p.Thr1115Cys
| Predicted by SNAP2: | A: N (87%), C: N (66%), D: D (66%), E: D (75%), F: D (63%), G: D (53%), H: D (75%), I: D (66%), K: D (85%), L: D (71%), M: D (53%), N: D (63%), P: D (75%), Q: D (63%), R: D (80%), S: N (82%), V: N (61%), W: D (80%), Y: D (71%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, V: N, W: N, Y: N, |
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[hide] Relative contribution of different transmembrane s... Pflugers Arch. 2014 Mar;466(3):477-90. doi: 10.1007/s00424-013-1317-x. Epub 2013 Aug 20. Wang W, El Hiani Y, Rubaiy HN, Linsdell P
Relative contribution of different transmembrane segments to the CFTR chloride channel pore.
Pflugers Arch. 2014 Mar;466(3):477-90. doi: 10.1007/s00424-013-1317-x. Epub 2013 Aug 20., [PMID:23955087]
Abstract [show]
The membrane-spanning part of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel comprises 12 transmembrane (TM) alpha-helices, arranged in 2 symmetrical groups of 6. However, those TMs that line the channel pore are not completely defined. We used patch clamp recording to compare the accessibility of cysteine-reactive reagents to cysteines introduced into different TMs. Several residues in TM11 were accessible to extracellular and/or intracellular cysteine reactive reagents; however, no reactive cysteines were identified in TMs 5 or 11. Two accessible residues in TM11 (T1115C and S1118C) were found to be more readily modified from the extracellular solution in closed channels, but more readily modified from the intracellular solution in open channels, as previously reported for T338C in TM6. However, the effects of mutagenesis at S1118 (TM11) on a range of pore functional properties were relatively minor compared to the large effects of mutagenesis at T338 (TM6). Our results suggest that the CFTR pore is lined by TM11 but not by TM5 or TM7. Comparison with previous works therefore suggests that the pore is lined by TMs 1, 6, 11, and 12, suggesting that the structure of the open channel pore is asymmetric in terms of the contributions of different TMs. Although TMs 6 and 11 appear to undergo similar conformational changes during channel opening and closing, the influence of these two TMs on the functional properties of the narrowest region of the pore is clearly unequal.
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No. Sentence Comment
4 Two accessible residues in TM11 (T1115C and S1118C) were found to be more readily modified from the extracellular solution in closed channels, but more readily modified from the intracellular solution in open channels, as previously reported for T338C in TM6.
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ABCC7 p.Thr1115Cys 23955087:4:33
status: NEW77 Note that while MTSES caused rapid inhibition of macroscopic current amplitude in T1115C and S1118C, inhibition of I1112C current was much slower (note different time scale for this mutant).
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ABCC7 p.Thr1115Cys 23955087:77:82
status: NEW111 b Example whole cell currents recorded continuously at +30 mV for constitutively active T1115C/ E1371Q and S1118C/E1371Q channels.
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ABCC7 p.Thr1115Cys 23955087:111:88
status: NEW112 In contrast to currents carried by T1115C and S1118C channels (see Fig. 3), these whole cell currents were not significantly affected by addition of 200 bc;M MTSES to the extracellular solution (black bars), even though these currents were positively identified as being carried by CFTR by sensitivity to GlyH-101 (50 bc;M, hatched bars).
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ABCC7 p.Thr1115Cys 23955087:112:35
status: NEW117 Application of MTSES (200 bc;M) following channel activation with PKA and ATP caused a decrease in macroscopic current amplitude in I1112C, T1115C and S1118C, but not in T1121C (Fig. 2a, b) or in I1109C, F1110C, F1111C, A1113C, V1114C, F1116C, or I1117C (Fig. 2c).
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ABCC7 p.Thr1115Cys 23955087:117:143
status: NEW123 Figure 3 confirms that application of external MTSES (200 bc;M) following channel activation with cAMP-stimulatory cocktail caused a decrease in whole cell current amplitude in T1115C, S1118C, and T1121C, but not in I1112C.
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ABCC7 p.Thr1115Cys 23955087:123:180
status: NEW127 State-dependent accessibility of T1115C and S1118C in TM11 Modification of T1115C and S1118C by both internal and external MTSES is reminiscent of the accessibility pattern observed for TM6 cysteine mutant T338C [42].
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ABCC7 p.Thr1115Cys 23955087:127:33
status: NEWX
ABCC7 p.Thr1115Cys 23955087:127:75
status: NEW137 As shown in Fig. 4a, c, the E1371Q mutation significantly accelerated the rate of modification of both T1115C and S1118C by intracellular MTSES, suggesting that these cysteines are more readily modified from the inside in open channels.
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ABCC7 p.Thr1115Cys 23955087:137:103
status: NEW199 Furthermore, using the same approach used previously to study side-dependent modification of T338C [42], we found that T1115C and S1118C were more readily modified from the extracellular solution in closed channels, but more readily modified from the intracellular solution in open channels (Fig. 4).
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ABCC7 p.Thr1115Cys 23955087:199:119
status: NEW