ABCC7 p.Asn1148Cys
| ClinVar: |
c.3444C>A
,
p.Asn1148Lys
?
, not provided
c.3443A>G , p.Asn1148Ser ? , not provided |
| CF databases: |
c.3443A>G
,
p.Asn1148Ser
(CFTR1)
?
,
c.3444C>A , p.Asn1148Lys (CFTR1) ? , This mutation was found by DGGE and direct DNA sequencing in a child with bronchiectasis and sweat test borderline. |
| Predicted by SNAP2: | A: D (66%), C: D (66%), D: D (80%), E: D (80%), F: D (75%), G: D (75%), H: D (80%), I: D (66%), K: D (63%), L: D (71%), M: D (71%), P: D (85%), Q: D (63%), R: D (66%), S: D (63%), T: D (66%), V: D (63%), W: D (91%), Y: D (80%), |
| Predicted by PROVEAN: | A: N, C: D, D: N, E: N, F: D, G: N, H: N, I: N, K: N, L: N, M: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: N, |
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[hide] Functional arrangement of the 12th transmembrane r... Pflugers Arch. 2011 Oct;462(4):559-71. Epub 2011 Jul 28. Qian F, El Hiani Y, Linsdell P
Functional arrangement of the 12th transmembrane region in the CFTR chloride channel pore based on functional investigation of a cysteine-less CFTR variant.
Pflugers Arch. 2011 Oct;462(4):559-71. Epub 2011 Jul 28., [PMID:21796338]
Abstract [show]
The membrane-spanning part of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel comprises 12 transmembrane (TM) alpha-helices, arranged into two pseudo-symmetrical groups of six. While TM6 in the N-terminal TMs is known to line the pore and to make an important contribution to channel properties, much less is known about its C-terminal counterpart, TM12. We have used patch clamp recording to investigate the accessibility of cytoplasmically applied cysteine-reactive reagents to cysteines introduced along the length of TM12 in a cysteine-less variant of CFTR. We find that methanethiosulfonate (MTS) reagents irreversibly modify cysteines substituted for TM12 residues N1138, M1140, S1141, T1142, Q1144, W1145, V1147, N1148, and S1149 when applied to the cytoplasmic side of open channels. Cysteines sensitive to internal MTS reagents were not modified by extracellular [2-(trimethylammonium)ethyl] MTS, consistent with MTS reagent impermeability. Both S1141C and T1142C could be modified by intracellular [2-sulfonatoethyl] MTS prior to channel activation; however, N1138C and M1140C, located deeper into the pore from its cytoplasmic end, were modified only after channel activation. Comparison of these results with previous work on CFTR-TM6 allows us to develop a model of the relative positions, functional contributions, and alignment of these two important TMs lining the CFTR pore. We also propose a mechanism by which these seemingly structurally symmetrical TMs make asymmetric contributions to the functional properties of the channel pore.
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No. Sentence Comment
62 b Example leak subtracted I-V relationships for N1138C, T1142C, V1147C, and N1148C, recorded from inside out membrane patches following maximal channel activation with PKA, ATP, and PPi.
X
ABCC7 p.Asn1148Cys 21796338:62:76
status: NEW64 As described in the text, whereas MTSES application always led to a decrease in macroscopic current amplitude in reactive mutants, the effects of MTSET were to decrease (e.g., N1138C, V1147C), increase (e.g., T1142C) or not significantly alter (e.g., N1148C) macroscopic current amplitude.
X
ABCC7 p.Asn1148Cys 21796338:64:251
status: NEW80 Application of MTSES (200 μM) or MTSET (2 mM) to the intracellular solution after channel activation with PKA, ATP, and PPi significantly altered macroscopic current amplitude in nine out of 19 cysteine-substituted mutants tested (N1138C, M1140C, S1141C, T1142C, Q1144C, W1145C, V1147C, N1148C, and S1149C; Figs. 1 and 2).
X
ABCC7 p.Asn1148Cys 21796338:80:293
status: NEW86 However, unlike previous findings in TM6 [9], we observed a third pattern for cysteines introduced closest to the putative cytoplasmic end of TM12 (V1147C, N1148C, and S1149C).
X
ABCC7 p.Asn1148Cys 21796338:86:156
status: NEW87 Here, macroscopic current amplitude was decreased by MTSES application but either decreased (V1147C, S1149C) or not significantly affected (N1148C) by MTSET application.
X
ABCC7 p.Asn1148Cys 21796338:87:140
status: NEW[hide] Structural basis for the channel function of a deg... J Gen Physiol. 2011 Nov;138(5):495-507. Bai Y, Li M, Hwang TC
Structural basis for the channel function of a degraded ABC transporter, CFTR (ABCC7).
J Gen Physiol. 2011 Nov;138(5):495-507., [PMID:22042986]
Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) is a member of the ATP-binding cassette (ABC) transporter superfamily, but little is known about how this ion channel that harbors an uninterrupted ion permeation pathway evolves from a transporter that works by alternately exposing its substrate conduit to the two sides of the membrane. Here, we assessed reactivity of intracellularly applied thiol-specific probes with cysteine residues substituted into the 12th transmembrane segment (TM12) of CFTR. Our experimental data showing high reaction rates of substituted cysteines toward the probes, strong blocker protection of cysteines against reaction, and reaction-induced alterations in channel conductance support the idea that TM12 of CFTR contributes to the lining of the ion permeation pathway. Together with previous work, these findings raise the possibility that pore-lining elements of CFTR involve structural components resembling those that form the substrate translocation pathway of ABC transporters. In addition, comparison of reaction rates in the open and closed states of the CFTR channel leads us to propose that upon channel opening, the wide cytoplasmic vestibule tightens and the pore-lining TM12 rotates along its helical axis. This simple model for gating conformational changes in the inner pore domain of CFTR argues that the gating transition of CFTR and the transport cycle of ABC proteins share analogous conformational changes. Collectively, our data corroborate the popular hypothesis that degradation of the cytoplasmic-side gate turned an ABC transporter into the CFTR channel.
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No. Sentence Comment
154 (A and B) Single-channel recordings at 50 mV show that application of MTSET+ increases unitary current amplitudes for cysless/N1148C (A) or cysless/W1145C (B).
X
ABCC7 p.Asn1148Cys 22042986:154:134
status: NEW155 Linear fits to single-channel current measurements at different voltages yield unitary conductance values for cysless/ N1148C (A) of 7.1 pS before (black) and 9.2 pS after (blue) MTSET+ treatment, for cysless/W1145C (B) of 7.6 pS before (black) and 10.1 pS after (blue) MTSET+ treatment.
X
ABCC7 p.Asn1148Cys 22042986:155:119
status: NEW180 Note that the modification is faster in the presence of ATP than in the absence of ATP for cysless/N1148C-CFTR channels (B), whereas it is slower in the presence of ATP than in the absence of ATP for cysless/S1141C-CFTR channels (C).
X
ABCC7 p.Asn1148Cys 22042986:180:99
status: NEW198 (C) Second-order rate constants (MTSES ) of Texas red MTSEA+ modification for cysless/ S1141C-, cysless/N1148C-, cysless/ I344C-, and cysless/M348C-CFTR channels.
X
ABCC7 p.Asn1148Cys 22042986:198:121
status: NEW[hide] Metal bridges illuminate transmembrane domain move... J Biol Chem. 2014 Oct 10;289(41):28149-59. doi: 10.1074/jbc.M114.593103. Epub 2014 Aug 20. El Hiani Y, Linsdell P
Metal bridges illuminate transmembrane domain movements during gating of the cystic fibrosis transmembrane conductance regulator chloride channel.
J Biol Chem. 2014 Oct 10;289(41):28149-59. doi: 10.1074/jbc.M114.593103. Epub 2014 Aug 20., [PMID:25143385]
Abstract [show]
Opening and closing of the cystic fibrosis transmembrane conductance regulator are controlled by ATP binding and hydrolysis by the cytoplasmic nucleotide-binding domains. Different conformational changes in the channel pore have been described during channel opening and closing; however, the relative importance of these changes to the process of gating the pore is not known. We have used patch clamp recording to identify high affinity Cd(2+) bridges formed between pairs of pore-lining cysteine residues introduced into different transmembrane alpha-helices (TMs). Seven Cd(2+) bridges were identified forming between cysteines in TMs 6 and 12. Interestingly, each of these Cd(2+) bridges apparently formed only in closed channels, and their formation stabilized the closed state. In contrast, a single Cd(2+) bridge identified between cysteines in TMs 1 and 12 stabilized the channel open state. Analysis of the pattern of Cd(2+) bridge formation in different channel states suggests that lateral separation and convergence of different TMs, rather than relative rotation or translation of different TMs, is the key conformational change that causes the channel pore to open and close.
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None has been submitted yet.
No. Sentence Comment
51 To investigate potential Cd2af9; bridges formed between pore-lining cysteine side chains exposed in the inner vestibule of the CFTR pore, we combined individual cysteines that we previously found to be accessible to cytoplasmically applied methanethiosulfonate reagents in three important pore-lining TMs: TM1 (K95C, Q98C) (13), TM6 (I344C, V345C, M348C, A349C) (15), and TM12 (M1140C, S1141C, T1142C, Q1144C, W1145C, V1147C, N1148C) (16), to generate a total of 50 double cysteine mutants (8 TM1:TM6; 14 TM1:TM12; 28 TM6:TM12).
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ABCC7 p.Asn1148Cys 25143385:51:429
status: NEW71 In contrast, the remaining seven double cysteine mutants, namely I344C/S1141C (Fig. 2, C and D), V345C/S1141C, M348C/ S1141C (Fig. 2, C and E), M348C/V1144C, M348C/W1145C, M348C/V1147C, and M348C/N1148C, all showed increased sensitivity to Cd2af9; , leading to a significant decrease in Ki as compared with either of the single cysteine mutants from which they were derived (estimated Ki values b0d; 50 òe;M; Fig. 3).
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ABCC7 p.Asn1148Cys 25143385:71:196
status: NEW137 Thus, M348C is able to form Cd2af9; bridges with cysteines at multiple positions in TM12 (S1141C, Q1144C, W1145C, V1147C, N1148C) (Fig. 8B), and S1141C is able to form Cd2af9; bridges with cysteines both in TM1 (K95C) and in TM6 (I344C, V345C, M348C) (Fig. 8C).
X
ABCC7 p.Asn1148Cys 25143385:137:125
status: NEW[hide] Localizing a gate in CFTR. Proc Natl Acad Sci U S A. 2015 Feb 24;112(8):2461-6. doi: 10.1073/pnas.1420676112. Epub 2015 Feb 9. Gao X, Hwang TC
Localizing a gate in CFTR.
Proc Natl Acad Sci U S A. 2015 Feb 24;112(8):2461-6. doi: 10.1073/pnas.1420676112. Epub 2015 Feb 9., [PMID:25675504]
Abstract [show]
Experimental and computational studies have painted a picture of the chloride permeation pathway in cystic fibrosis transmembrane conductance regulator (CFTR) as a short narrow tunnel flanked by wider inner and outer vestibules. Although these studies also identified a number of transmembrane segments (TMs) as pore-lining, the exact location of CFTR's gate(s) remains unknown. Here, using a channel-permeant probe, [Au(CN)2](-), we provide evidence that CFTR bears a gate that coincides with the predicted narrow section of the pore defined as residues 338-341 in TM6. Specifically, cysteines introduced cytoplasmic to the narrow region (i.e., positions 344 in TM6 and 1148 in TM12) can be modified by intracellular [Au(CN)2](-) in both open and closed states, corroborating the conclusion that the internal vestibule does not harbor a gate. However, cysteines engineered to positions external to the presumed narrow region (e.g., 334, 335, and 337 in TM6) are all nonreactive toward cytoplasmic [Au(CN)2](-) in the absence of ATP, whereas they can be better accessed by extracellular [Au(CN)2](-) when the open probability is markedly reduced by introducing a second mutation, G1349D. As [Au(CN)2](-) and chloride ions share the same permeation pathway, these results imply a gate is situated between amino acid residues 337 and 344 along TM6, encompassing the very segment that may also serve as the selectivity filter for CFTR. The unique position of a gate in the middle of the ion translocation pathway diverges from those seen in ATP-binding cassette (ABC) transporters and thus distinguishes CFTR from other members of the ABC transporter family.
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None has been submitted yet.
No. Sentence Comment
192 [Au(CN)2]- , forskolin, with G1349D, /M/s Outside R334C 189 &#b1; 39 - 403 &#b1; 20 537 &#b1; 56 K335C - - 56 &#b1; 9 1,809 &#b1; 201 F337C 437 &#b1; 49 - 20 &#b1; 3 32 &#b1; 6 T338C 752 &#b1; 59 - 1,135 &#b1; 166 118 &#b1; 18 Inside I344C 32 &#b1; 5 37 &#b1; 4 - - N1148C 437 &#b1; 66 2,089 &#b1; 130 - - Residues located extracellularly (extra.)
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ABCC7 p.Asn1148Cys 25675504:192:266
status: NEW