ABCMdb

PMID: 9524141

Linsdell P, Hanrahan JW
Adenosine triphosphate-dependent asymmetry of anion permeation in the cystic fibrosis transmembrane conductance regulator chloride channel.
J Gen Physiol. 1998 Apr;111(4):601-14., [PubMed]

Sentences

No. Mutations Sentence Comment

18 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu m e t h o d s Experiments were carried out on baby hamster kidney (BHK) or Chinese hamster ovary (CHO) cells stably expressing either wild-type or mutant (K335E or R347D) CFTR (Tabcharani et al., 1991, 1993; Linsdell and Hanrahan, 1996a). Login to comment 131 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu To determine whether gluconate currents were carried directly via CFTR, we examined gluconate efflux mediated by two low conductance CFTR pore mutants, R347D and K335E (Tabcharani et al., 1993). Login to comment 133 ABCC7 p.Arg347Asp ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu ABCC7 p.Lys335Glu Both R347D (Fig. 7 A) and K335E (Fig. 7 B) had similar permeabilities to gluconate in the intracellular solution under biionic conditions to that of wild-type CFTR (PGluconate/PCl ϭ 0.069 Ϯ 0.010, n ϭ 9, for R347D and 0.064 Ϯ 0.008, n ϭ 7, for K335E), suggesting that relative permeability to large organic anions from the intracellular solution is not disrupted in either of these mutants. Login to comment 148 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu 3.9 fA (n ϭ 3) for R347D and 18.1 Ϯ 3.4 fA (n ϭ 5) for K335E, in both cases significantly smaller than wild type under these conditions (P Ͻ 0.05, two-tailed t test). Login to comment 151 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu To determine whether gluconate currents were carried directly via CFTR, we examined gluconate efflux mediated by two low conductance CFTR pore mutants, R347D and K335E (Tabcharani et al., 1993). Login to comment 153 ABCC7 p.Arg347Asp ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu ABCC7 p.Lys335Glu Both R347D (Fig. 7 A) and K335E (Fig. 7 B) had similar permeabilities to gluconate in the intracellular solution under biionic conditions to that of wild-type CFTR (PGluconate/PCl 5 0.069 6 0.010, n 5 9, for R347D and 0.064 6 0.008, n 5 7, for K335E), suggesting that relative permeability to large organic anions from the intracellular solution is not disrupted in either of these mutants. Login to comment 160 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu Both R347D (A) and K335E (B) mediate macroscopic gluconate efflux with a similar apparent gluconate permeability to wild type (see Figs. 1 A, 2 B, 3, B and C, 5 D, and 8, A and B). Login to comment 161 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu (C and D) Relationship between mean gluconate current (I) and current variance (␴2) at -50 mV under symmetrical ionic conditions for R347D (C) and K335E (D), calculated as described in Fig. 6 A. Login to comment 168 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu 3.9 fA (n 5 3) for R347D and 18.1 6 3.4 fA (n 5 5) for K335E, in both cases significantly smaller than wild type under these conditions (P , 0.05, two-tailed t test). Login to comment 180 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu Both R347D (A) and K335E (B) mediate macroscopic gluconate efflux with a similar apparent gluconate permeability to wild type (see Figs. 1 A, 2 B, 3, B and C, 5 D, and 8, A and B). Login to comment 181 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu (C and D) Relationship between mean gluconate current (I) and current variance (s2) at 250 mV under symmetrical ionic conditions for R347D (C) and K335E (D), calculated as described in Fig. 6 A. Login to comment 210 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu However, anion export in BHK cell patches was due to CFTR itself and not the result of modification of an anion transporter endogenous to these cells, since the apparent unitary gluconate current amplitude was significantly reduced in two CFTR mutants with reduced Cl- conductance, R347D and K335E (Fig. 7). Login to comment 230 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu However, anion export in BHK cell patches was due to CFTR itself and not the result of modification of an anion transporter endogenous to these cells, since the apparent unitary gluconate current amplitude was significantly reduced in two CFTR mutants with reduced Cl2 conductance, R347D and K335E (Fig. 7). Login to comment 249 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu We thank Shu-Xian Zheng and Jie Liao for technical assistance and Dr. J.M. Rommens (Hospital for Sick Children, Toronto, Ontario, Canada) for providing R347D and K335E cDNA. Login to comment 269 ABCC7 p.Arg347Asp ABCC7 p.Lys335Glu We thank Shu-Xian Zheng and Jie Liao for technical assistance and Dr. J.M. Rommens (Hospital for Sick Children, Toronto, Ontario, Canada) for providing R347D and K335E cDNA. Login to comment 372 ABCC7 p.Arg347Asp Interaction of channel blockers with R347D-CFTR. Login to comment 391 ABCC7 p.Arg347Asp Interaction of channel blockers with R347D-CFTR. Login to comment