ABCC7 p.Gly314Asp

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PMID: 9922376 [PubMed] Dawson DC et al: "CFTR: mechanism of anion conduction."
No. Sentence Comment
598 Mixtures of the TM2 and TM6 peptides producedmoderately impaired in G314A CFTR, and unaffected in G314D CFTR.
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ABCC7 p.Gly314Asp 9922376:598:98
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PMID: 9512029 [PubMed] Mansoura MK et al: "Cystic fibrosis transmembrane conductance regulator (CFTR) anion binding as a probe of the pore."
No. Sentence Comment
62 Expression levels Wild-type and 11 mutant CFTR constructs were used in this study: G91A, G91E, G91R, G314A, G314D, G314E, G314Q, K335R, K335A, K335D, and K335E.
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ABCC7 p.Gly314Asp 9512029:62:108
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116 It was of particular interest that the introduction of a glutamine (G314Q) also produced increased conductance ratios for the highly permeant anions and I, whereas the aspartic-acid-substituted construct (G314D) was not different from wtCFTR.
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ABCC7 p.Gly314Asp 9512029:116:205
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131 The behavior of G314D CFTR was virtually identical to that of wtCFTR.
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ABCC7 p.Gly314Asp 9512029:131:16
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135 There was no readily discernible voltage dependence to the dose-dependent attenuation of wtCFTR conductance by SCN; and similar results were obtained for G314D and G314A.
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ABCC7 p.Gly314Asp 9512029:135:154
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136 In the case of the G314E and G314Q mutants, however, the SCN effect appeared to be moderately voltage dependent (Fig. 2 TABLE 2 Summary of permeability and conductance ratios from anion substitution experiments n SCN NO3 Br HCOO I A.
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ABCC7 p.Gly314Asp 9512029:136:154
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137 Permeability Ratios Wild type 4-9 3.42 Ϯ 0.28 1.42 Ϯ 0.04 1.22 Ϯ 0.02 0.39 Ϯ 0.01 0.44 Ϯ 0.03 G91A 3-6 3.24 Ϯ 0.26 1.53 Ϯ 0.04 1.27 Ϯ 0.02 0.37 Ϯ 0.04 0.40 Ϯ 0.04 G91E 3-7 3.50 Ϯ 0.54 1.59 Ϯ 0.04 1.27 Ϯ 0.01 0.35 Ϯ 0.01 0.51 Ϯ 0.04 G91R 3-4 5.26 ؎ 0.46* 1.60 Ϯ 0.03 1.40 ؎ 0.01* 0.32 Ϯ 0.04 0.64 ؎ 0.04* G314A 3-4 2.87 Ϯ 0.17 1.45 Ϯ 0.03 1.19 Ϯ 0.02 0.31 Ϯ 0.03 0.33 Ϯ 0.03 G314D 4 3.42 Ϯ 0.34 1.44 Ϯ 0.05 1.25 Ϯ 0.04 0.33 Ϯ 0.03 0.51 Ϯ 0.05 G314E 3-4 3.72 Ϯ 0.56 1.65 ؎ 0.09* 1.35 ؎ 0.03* 0.49 Ϯ 0.04 0.53 Ϯ 0.04 G314Q 3-4 3.89 Ϯ 0.37 1.62 Ϯ 0.11 1.27 Ϯ 0.04 0.36 Ϯ 0.03 0.62 Ϯ 0.05 K335R 3-5 3.44 Ϯ 0.29 1.35 Ϯ 0.04 1.22 Ϯ 0.03 0.40 Ϯ 0.05 0.41 Ϯ 0.07 K335A 5-6 5.34 ؎ 0.58* 1.48 Ϯ 0.06 1.28 Ϯ 0.04 0.37 Ϯ 0.03 0.60 Ϯ 0.06 K335D 4-6 3.02 Ϯ 0.19 1.50 Ϯ 0.03 1.10 ؎ 0.02* 0.54 ؎ 0.04* 0.65 ؎ 0.06* K335E 5-8 3.64 Ϯ 0.21 1.48 Ϯ 0.06 1.29 Ϯ 0.03 0.46 Ϯ 0.04 1.10 ؎ 0.04* B. Conductance Ratios Wild type 4-9 0.14 Ϯ 0.02 0.75 Ϯ 0.02 0.64 Ϯ 0.02 0.52 Ϯ 0.03 0.18 Ϯ 0.03 G91A 3-6 0.14 Ϯ 0.01 0.77 Ϯ 0.02 0.61 Ϯ 0.02 0.47 Ϯ 0.02 0.19 Ϯ 0.02 G91E 3-7 0.15 Ϯ 0.03 0.73 Ϯ 0.02 0.60 Ϯ 0.01 0.50 Ϯ 0.04 0.30 Ϯ 0.02 G91R 3-4 0.14 Ϯ 0.00 0.84 Ϯ 0.01 0.63 Ϯ 0.01 0.32 ؎ 0.01* 0.14 Ϯ 0.01 G314A 3-4 0.30 Ϯ 0.09 0.89 ؎ 0.01* 0.66 Ϯ 0.01 0.48 Ϯ 0.09 0.24 Ϯ 0.01 G314D 4 0.28 Ϯ 0.05 0.82 Ϯ 0.01 0.70 Ϯ 0.02 0.49 Ϯ 0.06 0.27 Ϯ 0.03 G314E 3-4 0.62 ؎ 0.07* 1.18 ؎ 0.04* 0.84 ؎ 0.05* 0.42 Ϯ 0.05 0.29 Ϯ 0.09 G314Q 3-4 0.63 ؎ 0.02* 1.01 ؎ 0.04* 0.82 ؎ 0.03* 0.50 Ϯ 0.02 0.42 ؎ 0.02* K335R 3-5 0.14 Ϯ 0.01 0.76 Ϯ 0.03 0.61 Ϯ 0.02 0.59 Ϯ 0.06 0.16 Ϯ 0.03 K335A 6 0.20 Ϯ 0.03 0.77 Ϯ 0.02 0.61 Ϯ 0.02 0.45 Ϯ 0.03 0.21 Ϯ 0.02 K335D 4-6 0.65 ؎ 0.04* 1.25 ؎ 0.02* 0.89 ؎ 0.02* 0.61 Ϯ 0.06 0.58 ؎ 0.06* K335E 5-8 0.50 ؎ 0.06* 1.19 ؎ 0.03* 0.89 ؎ 0.02* 0.53 Ϯ 0.03 0.48 ؎ 0.03* (A) The apparent permeability ratios (PS/PCl) for each substitute anion were calculated from the shift in reversal potential using the Goldman-Hodgkin-Katz relation (noted in Materials and Methods).
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ABCC7 p.Gly314Asp 9512029:137:524
status: NEW
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ABCC7 p.Gly314Asp 9512029:137:1754
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169 TABLE 4 Quantitative analyses of the macroscopic I-V shape changes Mutant ⌬ Net charge n RR g(ϩ30)/g(-30) RR/RRWT Wild type 5 1.220 Ϯ 0.06 1.00 G91A 0 4 1.293 Ϯ 0.06 1.06 G91E -1 5 1.512 ؎ 0.10* 1.24 G91R 1 4 8.041 ؎ 0.87* 6.59 G314A 0 4 1.201 Ϯ 0.09 0.98 G314D -1 4 1.362 Ϯ 0.08 1.12 G314E -1 7 1.405 Ϯ 0.08 1.15 G314Q 0 5 1.376 Ϯ 0.10 1.13 K335R 0 4 1.209 Ϯ 0.06 0.99 K335A -1 4 1.295 Ϯ 0.07 1.06 K335D -2 5 0.762 ؎ 0.02* 0.62 K335E -2 4 0.919 ؎ 0.02* 0.75 The slope conductance was measured at ϩ30 mV and -30 mV with respect to the reversal potential.
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ABCC7 p.Gly314Asp 9512029:169:299
status: NEW
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ABCC7 p.Gly314Asp 9512029:169:310
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171 TABLE 3 The permeability ratio (PSCN/PCl) is independent of the mole fraction of [SCN]0 for wtCFTR and the G314 variants [SCN]/{[SCN]ϩ[Cl]} n PSCN/PCl 0.02 0.05 0.10 0.20 0.50 0.90 Wild type 12 3.82 Ϯ 0.50 4.43 Ϯ 0.57 4.58 Ϯ 0.48 4.69 Ϯ 0.43 4.66 Ϯ 0.38 4.44 Ϯ 0.35 G314A 9 4.32 Ϯ 0.73 3.78 Ϯ 0.53 3.81 Ϯ 0.47 3.79 Ϯ 0.34 3.82 Ϯ 0.29 3.72 Ϯ 0.25 G314D 3 2.99 Ϯ 0.26 2.56 Ϯ 1.05 2.82 Ϯ 1.07 2.68 Ϯ 0.97 2.87 Ϯ 0.65 2.89 Ϯ 0.43 G314E 6 4.48 Ϯ 1.05 4.01 Ϯ 0.69 4.17 Ϯ 0.62 4.15 Ϯ 0.59 3.96 Ϯ 0.41 3.82 Ϯ 0.40 G314Q 3 5.39 Ϯ 0.57 4.49 Ϯ 0.58 4.69 Ϯ 1.26 4.05 Ϯ 1.26 3.86 Ϯ 1.47 3.68 Ϯ 1.51 The permeability ratios were calculated from the shift in reversal potential using the Goldman-Hodgkin-Katz equation.
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ABCC7 p.Gly314Asp 9512029:171:424
status: NEW
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173 TABLE 5 Concentration-dependent activation of wtCFTR, G91, G314, and K335 variants by IBMX in the presence of 10 ␮M forskolin Mutant n K1/2(IBMX) (mM) Wild type 15 0.35 Ϯ 0.04 G91A 5 0.42 Ϯ 0.06 G91E 8 0.51 ؎ 0.06* G91R 5 0.49 Ϯ 0.09 G314A 10 1.21 ؎ 0.11* G314D 3 1.35 ؎ 0.16* G314E 8 6.39 ؎ 1.35* G314Q 4 14.26 ؎ 6.64* K335R 4 0.46 Ϯ 0.04 K335A 2 0.35 Ϯ 0.15 K335D 7 0.87 ؎ 0.13* K335E 3 0.95 ؎ 0.07* The steady-state slope conductance was measured at -60 mV as increasing concentrations of IBMX (0.02-5.0 mM) were added to the perfusate in the continued presence of 10 mM forskolin.
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ABCC7 p.Gly314Asp 9512029:173:292
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180 It is noteworthy that, although the activation of G314D CFTR was significantly compromised, SCN binding was virtually identical to that seen with wtCFTR.
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ABCC7 p.Gly314Asp 9512029:180:50
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194 Finally, in at least one mutant, G314D, the effect of [SCN]o on conductance was unaffected despite the fact that sensitivity to activation by IBMX was severely compromised.
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ABCC7 p.Gly314Asp 9512029:194:33
status: NEW
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198 The results presented here are consistent with the notion that the binding of anions within the CFTR pore is a sensitive indicator of changes in pore structure whereas permeability ratios appear to be rather insensitive to similar TABLE 6 Qualitative summary of the functional consequences of mutations at G91, G314, and K335 Property G91 (TM1) K335 (TM6) G314 (TM5) G91A G91E G91R K335R K335A K335D K335E G314A G314D G314E G314Q I-V shape - - ϩϩϩ - - ϩϩ ϩ - - - - Psub/PCl - - - - - - ϩϩ - - - - gsub/gCl - - - - - ϩϩϩ ϩϩϩ ϩϩ - ϩϩϩ ϩϩϩ SCN- binding - - - - - ϩϩϩ ϩϩϩ ϩϩ - ϩϩϩϩ ϩϩϩϩ Activation - - - - - ϩϩ ϩϩ ϩϩϩ ϩϩϩ ϩϩϩϩ ϩϩϩϩ Results are expressed as follows: -, function of the CFTR construct with the indicated substitution was indistinguishable from wild type; ϩ to ϩϩϩϩ, semiquantitative indication of the magnitude of the change in the function compared with wild type.
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ABCC7 p.Gly314Asp 9512029:198:412
status: NEW
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236 Simply introducing a negative charge at G314 (G314D) was not sufficient to reduce SCN binding, suggesting that the destabilizing effect was not electrostatic in nature, but rather that the role of TM5 may be to provide some element of conformation necessary for the tight binding of anions to another residue, such as R347 in TM6 (Tabcharani et al., 1993).
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ABCC7 p.Gly314Asp 9512029:236:46
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273 In G314D CFTR, however, apparent SCN binding was similar to that seen with wtCFTR, but activation was significantly impaired, suggesting that 1) sensitivity to activation by IBMX is, if anything, even more sensitive than anion binding to alterations in the structure of TM5 and 2) there is no obligatory relation between anion binding and activation.
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ABCC7 p.Gly314Asp 9512029:273:3
status: NEW
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117 It was of particular interest that the introduction of a glutamine (G314Q) also produced increased conductance ratios for the highly permeant anions and I, whereas the aspartic-acid-substituted construct (G314D) was not different from wtCFTR.
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ABCC7 p.Gly314Asp 9512029:117:205
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132 The behavior of G314D CFTR was virtually identical to that of wtCFTR.
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ABCC7 p.Gly314Asp 9512029:132:16
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138 Permeability Ratios Wild type 4-9 3.42 afe; 0.28 1.42 afe; 0.04 1.22 afe; 0.02 0.39 afe; 0.01 0.44 afe; 0.03 G91A 3-6 3.24 afe; 0.26 1.53 afe; 0.04 1.27 afe; 0.02 0.37 afe; 0.04 0.40 afe; 0.04 G91E 3-7 3.50 afe; 0.54 1.59 afe; 0.04 1.27 afe; 0.01 0.35 afe; 0.01 0.51 afe; 0.04 G91R 3-4 5.26 d1e; 0.46* 1.60 afe; 0.03 1.40 d1e; 0.01* 0.32 afe; 0.04 0.64 d1e; 0.04* G314A 3-4 2.87 afe; 0.17 1.45 afe; 0.03 1.19 afe; 0.02 0.31 afe; 0.03 0.33 afe; 0.03 G314D 4 3.42 afe; 0.34 1.44 afe; 0.05 1.25 afe; 0.04 0.33 afe; 0.03 0.51 afe; 0.05 G314E 3-4 3.72 afe; 0.56 1.65 d1e; 0.09* 1.35 d1e; 0.03* 0.49 afe; 0.04 0.53 afe; 0.04 G314Q 3-4 3.89 afe; 0.37 1.62 afe; 0.11 1.27 afe; 0.04 0.36 afe; 0.03 0.62 afe; 0.05 K335R 3-5 3.44 afe; 0.29 1.35 afe; 0.04 1.22 afe; 0.03 0.40 afe; 0.05 0.41 afe; 0.07 K335A 5-6 5.34 d1e; 0.58* 1.48 afe; 0.06 1.28 afe; 0.04 0.37 afe; 0.03 0.60 afe; 0.06 K335D 4-6 3.02 afe; 0.19 1.50 afe; 0.03 1.10 d1e; 0.02* 0.54 d1e; 0.04* 0.65 d1e; 0.06* K335E 5-8 3.64 afe; 0.21 1.48 afe; 0.06 1.29 afe; 0.03 0.46 afe; 0.04 1.10 d1e; 0.04* B. Conductance Ratios Wild type 4-9 0.14 afe; 0.02 0.75 afe; 0.02 0.64 afe; 0.02 0.52 afe; 0.03 0.18 afe; 0.03 G91A 3-6 0.14 afe; 0.01 0.77 afe; 0.02 0.61 afe; 0.02 0.47 afe; 0.02 0.19 afe; 0.02 G91E 3-7 0.15 afe; 0.03 0.73 afe; 0.02 0.60 afe; 0.01 0.50 afe; 0.04 0.30 afe; 0.02 G91R 3-4 0.14 afe; 0.00 0.84 afe; 0.01 0.63 afe; 0.01 0.32 d1e; 0.01* 0.14 afe; 0.01 G314A 3-4 0.30 afe; 0.09 0.89 d1e; 0.01* 0.66 afe; 0.01 0.48 afe; 0.09 0.24 afe; 0.01 G314D 4 0.28 afe; 0.05 0.82 afe; 0.01 0.70 afe; 0.02 0.49 afe; 0.06 0.27 afe; 0.03 G314E 3-4 0.62 d1e; 0.07* 1.18 d1e; 0.04* 0.84 d1e; 0.05* 0.42 afe; 0.05 0.29 afe; 0.09 G314Q 3-4 0.63 d1e; 0.02* 1.01 d1e; 0.04* 0.82 d1e; 0.03* 0.50 afe; 0.02 0.42 d1e; 0.02* K335R 3-5 0.14 afe; 0.01 0.76 afe; 0.03 0.61 afe; 0.02 0.59 afe; 0.06 0.16 afe; 0.03 K335A 6 0.20 afe; 0.03 0.77 afe; 0.02 0.61 afe; 0.02 0.45 afe; 0.03 0.21 afe; 0.02 K335D 4-6 0.65 d1e; 0.04* 1.25 d1e; 0.02* 0.89 d1e; 0.02* 0.61 afe; 0.06 0.58 d1e; 0.06* K335E 5-8 0.50 d1e; 0.06* 1.19 d1e; 0.03* 0.89 d1e; 0.02* 0.53 afe; 0.03 0.48 d1e; 0.03* (A) The apparent permeability ratios (PS/PCl) for each substitute anion were calculated from the shift in reversal potential using the Goldman-Hodgkin-Katz relation (noted in Materials and Methods).
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ABCC7 p.Gly314Asp 9512029:138:524
status: NEW
X
ABCC7 p.Gly314Asp 9512029:138:1754
status: NEW
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