ABCC7 p.Thr1121Cys

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PMID: 19381710 [PubMed] Fatehi M et al: "Novel residues lining the CFTR chloride channel pore identified by functional modification of introduced cysteines."
No. Sentence Comment
71 As described previously for modification of cysteines introduced into TM6 (Fatehi and Linsdell 2008) and the extracellular loop between TMs 1 and 2 (Zhou et al. 2008), MTSET and MTSES altered the IREL-V shape in S1118C, T1121C, T1122C, G1127C, V1129C, I1131C and I1132C.
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ABCC7 p.Thr1121Cys 19381710:71:220
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72 Of 21 cysteine mutants studied, only six significantly altered I-V relationship shape in the absence of external MTS reagents (Fig. 3a), with S1118C, T1121C, T1122C, G1127C and A1136C all causing significant inward rectification and V1129C showing outward rectification.
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ABCC7 p.Thr1121Cys 19381710:72:150
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84 Unitary currents at depolarized voltages were significantly decreased in S1118C, T1121C, T1122C and G1127C and significantly increased in V1129C (Fig. 5b).
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ABCC7 p.Thr1121Cys 19381710:84:81
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85 This resulted in changes in the shape of the i-V relationship, causing inward rectification in the case of S1118C, T1121C, T1122C and G1127C and outward rectification in the case of V1129C (Figs. 4b, 5c).
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ABCC7 p.Thr1121Cys 19381710:85:115
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91 Indeed, changes in unitary current amplitude were observed in S1118C, T1121C, T1122C, G1127C, V1129C, I1131C and I1132C, but not wild-type, when MTS reagents were included in the pipette solution (Fig. 6).
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ABCC7 p.Thr1121Cys 19381710:91:72
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118 Four mutations (S1118C, T1121C, T1122C, G1127C) led to significant decreases in unitary current amplitude (Fig. 5b), which were relatively strongly affected by MTS modification-in each case conductance was further decreased by reaction with MTSES and increased to near wild-type levels by MTSET (Fig. 9a).
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ABCC7 p.Thr1121Cys 19381710:118:24
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124 Under these conditions, SCN- block was significantly strengthened in I1132C (at hyperpolarized and depolarized voltages), S1118C (at hyperpolarized voltages), T1121C and V1129C (at depolarized voltages) and I1131C (at very depolarized voltages only) Fig. 4 Single-channel currents carried by cysteine mutant forms of CFTR.
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ABCC7 p.Thr1121Cys 19381710:124:159
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125 a Example single-channel currents carried by wild-type, S1118C, T1121C, T1122C and V1129C, at membrane potentials of ?60 (top) and -60 (bottom) mV.
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ABCC7 p.Thr1121Cys 19381710:125:64
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133 Under these conditions, SCN- permeability was significantly increased in S1118C and (to a lesser extent) T1122C and G1127C and unaltered in T1121C, V1129C, I1131C and I1132C (Fig. 11).
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ABCC7 p.Thr1121Cys 19381710:133:140
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158 Of the seven mutants that were functionally modified by MTS reagents, five (S1118C, T1121C, T1122C, G1127C, V1129C) also showed significantly altered unitary current amplitude in the absence of MTS modification (Figs. 4, 5).
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ABCC7 p.Thr1121Cys 19381710:158:84
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161 a S1118C (d), T1121C (j), T1122C (), G1127C (h); b V1129C (m), I1131C (r), I1132C (.).
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ABCC7 p.Thr1121Cys 19381710:161:14
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183 We speculate that one group of reactive mutants (S1118C, T1121C, T1122C, G1127C) is located relatively deep in the pore from the outside and that the other (V1129C, Fig. 11 Thiocyanate permeability of mutants.
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ABCC7 p.Thr1121Cys 19381710:183:57
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188 In this scenario, charge-neutral mutations deeper in the pore (S1118C, T1121C, T1122C, G1127C) (Fig. 9a) disrupt Cl- movement in the pore in a nonelectrostatic fashion, leading to reduced unitary currents at depolarized voltages, as described previously for TM6 mutations (McDonough et al. 1994; Linsdell et al. 1998; Linsdell 2001a).
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ABCC7 p.Thr1121Cys 19381710:188:71
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PMID: 23955087 [PubMed] Wang W et al: "Relative contribution of different transmembrane segments to the CFTR chloride channel pore."
No. Sentence Comment
78 MTSES did not affect T1121C currents; however, these were inhibited by CFTRinh-172 (5 bc;M; hatched bar).
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ABCC7 p.Thr1121Cys 23955087:78:21
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117 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.Thr1121Cys 23955087:117:173
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122 Previously it was shown that S1118C, T1121C, and T1122C-but not F1116C, I1117C, I1119C, or L1120C-are accessible to externally applied MTS reagents [10].
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ABCC7 p.Thr1121Cys 23955087:122:37
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123 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.Thr1121Cys 23955087:123:200
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