ABCC7 p.Glu1124Cys
| Predicted by SNAP2: | A: N (66%), C: N (66%), D: N (66%), F: N (53%), G: N (53%), H: N (57%), I: N (57%), K: N (53%), L: N (53%), M: N (53%), N: N (66%), P: D (75%), Q: N (61%), R: D (53%), S: N (66%), T: N (66%), V: N (57%), W: D (85%), Y: D (59%), |
| Predicted by PROVEAN: | A: N, C: N, D: 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, T: N, V: N, W: N, Y: N, |
[switch to compact view]
Comments [show]
None has been submitted yet.
[hide] Three charged amino acids in extracellular loop 1 ... J Gen Physiol. 2014 Aug;144(2):159-79. doi: 10.1085/jgp.201311122. Epub 2014 Jul 14. Cui G, Rahman KS, Infield DT, Kuang C, Prince CZ, McCarty NA
Three charged amino acids in extracellular loop 1 are involved in maintaining the outer pore architecture of CFTR.
J Gen Physiol. 2014 Aug;144(2):159-79. doi: 10.1085/jgp.201311122. Epub 2014 Jul 14., [PMID:25024266]
Abstract [show]
The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) bears six extracellular loops (ECL1-6); ECL1 is the site of several mutations associated with CF. Mutation R117H has been reported to reduce current amplitude, whereas D110H, E116K, and R117C/L/P may impair channel stability. We hypothesized that these amino acids might not be directly involved in ion conduction and permeation but may contribute to stabilizing the outer vestibule architecture in CFTR. We used cRNA injected oocytes combined with electrophysiological techniques to test this hypothesis. Mutants bearing cysteine at these sites were not functionally modified by extracellular MTS reagents and were blocked by GlyH-101 similarly to WT-CFTR. These results suggest that these three residues do not contribute directly to permeation in CFTR. In contrast, mutants D110R-, E116R-, and R117A-CFTR exhibited instability of the open state and significantly shortened burst duration compared with WT-CFTR and failed to be locked into the open state by AMP-PNP (adenosine 5'-(beta,gamma-imido) triphosphate); charge-retaining mutants showed mainly the full open state with comparably longer open burst duration. These interactions suggest that these ECL1 residues might be involved in maintaining the outer pore architecture of CFTR. A CFTR homology model suggested that E116 interacts with R104 in both the closed and open states, D110 interacts with K892 in the fully closed state, and R117 interacts with E1126 in the open state. These interactions were confirmed experimentally. The results suggest that D110, E116, and R117 may contribute to stabilizing the architecture of the outer pore of CFTR by interactions with other charged residues.
Comments [show]
None has been submitted yet.
No. Sentence Comment
238 We did not observe any evidence of covalent modification of E1124C-, D891C-, or R899C- CFTR; there was no change in current upon exposure to either MTSET+ or MTSES&#e032; .
X
ABCC7 p.Glu1124Cys 25024266:238:60
status: NEW239 E1124C-CFTR current was transiently increased by MTSET+ , but in a noncovalent manner (Fig. S4 B).
X
ABCC7 p.Glu1124Cys 25024266:239:0
status: NEW