ABCC7 p.Cys128Ser
| CF databases: |
c.382T>C
,
p.Cys128Arg
(CFTR1)
D
,
|
| Predicted by SNAP2: | A: N (82%), D: D (75%), E: D (75%), F: D (75%), G: N (78%), H: D (75%), I: D (71%), K: D (80%), L: D (75%), M: D (71%), N: D (66%), P: D (66%), Q: D (75%), R: D (80%), S: N (87%), T: N (61%), V: N (57%), W: D (85%), Y: D (80%), |
| Predicted by PROVEAN: | A: N, D: D, E: D, F: N, G: D, H: D, I: N, K: D, L: N, M: N, N: D, P: D, Q: D, R: D, S: N, T: D, V: N, W: D, Y: N, |
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[hide] In vivo phosphorylation of CFTR promotes formation... EMBO J. 2006 Oct 18;25(20):4728-39. Epub 2006 Oct 12. Mense M, Vergani P, White DM, Altberg G, Nairn AC, Gadsby DC
In vivo phosphorylation of CFTR promotes formation of a nucleotide-binding domain heterodimer.
EMBO J. 2006 Oct 18;25(20):4728-39. Epub 2006 Oct 12., 2006-10-18 [PMID:17036051]
Abstract [show]
The human ATP-binding cassette (ABC) protein CFTR (cystic fibrosis transmembrane conductance regulator) is a chloride channel, whose dysfunction causes cystic fibrosis. To gain structural insight into the dynamic interaction between CFTR's nucleotide-binding domains (NBDs) proposed to underlie channel gating, we introduced target cysteines into the NBDs, expressed the channels in Xenopus oocytes, and used in vivo sulfhydryl-specific crosslinking to directly examine the cysteines' proximity. We tested five cysteine pairs, each comprising one introduced cysteine in the NH(2)-terminal NBD1 and another in the COOH-terminal NBD2. Identification of crosslinked product was facilitated by co-expression of NH(2)-terminal and COOH-terminal CFTR half channels each containing one NBD. The COOH-terminal half channel lacked all native cysteines. None of CFTR's 18 native cysteines was found essential for wild type-like, phosphorylation- and ATP-dependent, channel gating. The observed crosslinks demonstrate that NBD1 and NBD2 interact in a head-to-tail configuration analogous to that in homodimeric crystal structures of nucleotide-bound prokaryotic NBDs. CFTR phosphorylation by PKA strongly promoted both crosslinking and opening of the split channels, firmly linking head-to-tail NBD1-NBD2 association to channel opening.
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No. Sentence Comment
180 CFTR with substitutions C128S, C225S, C343S and C866S was provided by Dr DC Dawson (OHSU, Portland, OR, USA).
X
ABCC7 p.Cys128Ser 17036051:180:24
status: NEW[hide] Functional Differences in Pore Properties Between ... J Membr Biol. 2011 Oct;243(1-3):15-23. Epub 2011 Jul 28. Holstead RG, Li MS, Linsdell P
Functional Differences in Pore Properties Between Wild-Type and Cysteine-Less Forms of the CFTR Chloride Channel.
J Membr Biol. 2011 Oct;243(1-3):15-23. Epub 2011 Jul 28., [PMID:21796426]
Abstract [show]
Studies of the structure and function of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel have been advanced by the development of functional channel variants in which all 18 endogenous cysteine residues have been mutated ("cys-less" CFTR). However, cys-less CFTR has a slightly higher single-channel conductance than wild-type CFTR, raising questions as to the suitability of cys-less as a model of the wild-type CFTR pore. We used site-directed mutagenesis and patch-clamp recording to investigate the origin of this conductance difference and to determine the extent of functional differences between wild-type and cys-less CFTR channel permeation properties. Our results suggest that the conductance difference is the result of a single substitution, of C343: the point mutant C343S has a conductance similar to cys-less, whereas the reverse mutation, S343C in a cys-less background, restores wild-type conductance levels. Other cysteine substitutions (C128S, C225S, C376S, C866S) were without effect. Substitution of other residues for C343 suggested that conductance is dependent on amino acid side chain volume at this position. A range of other functional pore properties, including interactions with channel blockers (Au[CN] (2) (-) , 5-nitro-2-[3-phenylpropylamino]benzoic acid, suramin) and anion permeability, were not significantly different between wild-type and cys-less CFTR. Our results suggest that functional differences between these two CFTR constructs are of limited scale and scope and result from a small change in side chain volume at position 343. These results therefore support the use of cys-less as a model of the CFTR pore region.
Comments [show]
None has been submitted yet.
No. Sentence Comment
4 Other cysteine substitutions (C128S, C225S, C376S, C866S) were without effect.
X
ABCC7 p.Cys128Ser 21796426:4:30
status: NEW58 In contrast, other point mutants studied (C128S, C225S, C276S, C866S) had conductances that were not significantly different from wild type but were significantly different from cys-less (Fig. 2d).
X
ABCC7 p.Cys128Ser 21796426:58:42
status: NEW