ABCMdb

ABCC7 p.Arg334Lys

None has been submitted yet.

Publications

PMID: 12679372 [PubMed] Gong X et al: "Molecular determinants and role of an anion binding site in the external mouth of the CFTR chloride channel pore."

No. Sentence Comment

53 Block of wild-type, R334C-, R334E-, R334H-, R334K-, R334L- and R334Q-CFTR by 100 mM and 1 mM intracellular Au(CN)2 _ are compared in Fig. 4B. Login to comment
54 Block was affected in all mutants, depending on the ionic conditions used, but was particularly weakened in R334C, R334E and R334K (Fig. 5A-C). Login to comment
93 As noted by Smith et al. (2001), this effect was clearly charge dependent, being strongest in R334E and weak (but still significant) in R334K. Login to comment
119 R334K greatly decreased Au(CN)2 _ affinity (Figs B and 5), increasing Kd(0) 4-7-fold under conditions of high extracellular Cl_ (Fig. 5A), and 14-24-fold with the impermeant gluconate ion in the extracellular solution (Fig. 5B), conditions under which Au(CN)2 _ binding is studied in relative isolation from interactions with other anions. Login to comment
141 With either Cl_ or gluconate in the extracellular solution, Au(CN)2 _ block was most dramatically weakened in the mutants R334C, R334E and R334K, which involve replacement of the positively charged arginine side chain with one neutral side chain (cysteine), one negatively charged side chain (glutamate) and one positively charged side chain Anion binding site in the CFTR pore outer mouthJ Physiol 549.2 395 (lysine). Login to comment

PMID: 15504721 [PubMed] Ge N et al: "Direct comparison of the functional roles played by different transmembrane regions in the cystic fibrosis transmembrane conductance regulator chloride channel pore."

No. Sentence Comment

45 Previously we showed that the TM6 mutant R334A did not express but characterized several other Arg-334 mutants (10, 28); in the present study we have used the charge conservative R334K mutant. Login to comment
76 However, the unitary conductance was drastically reduced by some mutations in TM1 (K95Q, Q98A, P99A) and TM6 (R334K, F337A) (Figs. 2-4). Login to comment
82 In most cases macroscopic I-V relationships were linear or weakly inwardly rectifying in the presence of symmetrical high Cl- concentra- tions (as quantified in Fig. 6), although particularly strong inward rectification was observed in Q98A, P99A, and R334K. Login to comment
102 The weakest block by Au(CN)2 - was observed in K95Q, T338A, R334K, and Q98A, consistent with these residues perhaps being associated with permeant anion binding sites inside the pore. Login to comment
119 Some mutants that significantly affect both unitary conductance and Au(CN)2 - block were found to be without effect on SCN- permeability (Q98A, V318A, R334K, K335A). Login to comment

PMID: 17673962 [PubMed] Zhou JJ et al: "Direct and indirect effects of mutations at the outer mouth of the cystic fibrosis transmembrane conductance regulator chloride channel pore."

No. Sentence Comment

23 However, all mutations studied, including the charge-conservative R334K, lead to significant weakening of Au(CN)2 À binding (Gong & Linsdell, 2003a), which is inconsistent with an electrostatic interaction. Login to comment
28 However, single-channel recording showed that all mutations at this site, including the charge-conservative R334K, lead to a dramatic decrease in the amplitude of unitary currents carried by ClÀ efflux through the pore (Gong & Linsdell, 2004). Login to comment
85 Figure 3 shows the blocking effects of internally applied Pt(NO2)4 2À in six different channel mutants (R334C, R334E, R334H, R334K, R334L, R334Q) under conditions of both low (Fig. 3a) and high (Fig. 3b) extracellular ClÀ concentration. Login to comment
91 With elevated extracellular ClÀ , the Kd(0) was significantly increased only in R334C and R334E; not significantly altered in R334K, R334L and R334Q; and significantly decreased in R334H (Fig. 5b). Login to comment
106 Comparison of the mean Kd estimated for suramin (at 0 mV) shows that R334C, R334E, R334K, R334L and R334Q were all associated with weakened suramin block, with only R334H failing to significantly affect suramin block (Fig. 7). Login to comment
129 Mean of data from three to eight patches. Fitted lines are to equation 1 as described in Figure 1 for wild type and R334Q and with the following parameters for other channel variants: R334C 4 mM external ClÀ , Kd(0) = 1362 lM, zd = À0.295; R334C 154 mM external ClÀ , Kd(0) = 836 lM, zd = À0.219; R334E 4 mM external ClÀ , Kd(0) = 759 lM, zd = À0.376; R334E 154 mM external ClÀ , Kd(0) = 564 lM, zd = À0.173; R334H 4 mM external ClÀ , Kd(0) = 140 lM, zd = À0.166; R334H 154 mM external ClÀ , Kd(0) = 119 lM, zd = À0.149; R334K 4 mM external ClÀ , Kd(0) = 143 lM, zd = À0.314; R334K 154 mM external ClÀ , Kd(0) = 317 lM, zd = À0.374; R334L 4 mM external ClÀ , Kd(0) = 176 lM, zd = À0.258; R334L 154 mM external ClÀ , Kd(0) = 284 lM, zd = À0.366 extracellular Pt(NO2)4 2À by normalizing current amplitude at the hyperpolarized extreme of the voltage range studied, -80 mV (Fig. 10b). Login to comment
139 However, it can be seen that for all R334 mutations except the charge-conservative R334K, current-voltage relationship shape was not strongly altered by the presence of Pt(NO2)4 2À in the extracellular solution. Login to comment
142 Considering only the data at +80 mV (Fig. 11d), where block of wild-type CFTR is strongest (Figs. 9, 10), the blocking effects of Pt(NO2)4 2À are slightly (but significantly) weakened in K95Q, R303Q and R334K (p < 0.05) but practically abolished in all other R334 mutants (p < 0.0005). Login to comment
143 In fact, only wild type, R334K, K95Q and R303Q - those mutants that retain a positive charge at position 334 - were significantly affected by 10 mM Pt(NO2)4 2À according to this analysis (as illustrated by the daggers in Fig. 11d, p < 0.001), whereas all mutants associated with removal of the positive charge at R334 showed no significant differences in the absence or presence of external Pt(NO2)4 2À (p > 0.15). Login to comment
159 These plots represent mean data from four to seven patches. Fitted lines are to equation 1 with the following parameters: wild type, Kd(0) = 2.51 lM, zd = À0.042; R334C, Kd(0) = 18.5 lM, zd = À0.056; R334E, Kd(0) = 25.0 lM, zd = À0.107; R334H, Kd(0) = 3.10 lM, zd = À0.085; R334K, Kd(0) = 6.31 lM, zd = À0.232; R334L, Kd(0) = 4.08 lM, zd = À0.061; R334Q, Kd(0) = 6.64 lM, zd = À0.239 with our previous suggestion that intracellular Au(CN)2 À blocks the channel by interacting directly with R334, several reasons prompt us to suggest that Pt(NO2)4 2À does not interact directly with the arginine side chain at this position. Login to comment
161 Second, Pt(NO2)4 2À block is significantly weakened in all of the six R334-mutated variants studied, including the charge-conservative R334K (Fig. 5a). Login to comment
185 In contrast, the charge-conservative R334K mutant showed only very slightly weakened block by external Pt(NO2)4 2À (Fig. 11d). Login to comment
200 Our results are also entirely consistent with extracellular Pt(NO2)4 2À ions screening the surface charge contributed by R334 (or by the substituted lysine in R334K), resulting in loss of electrostatic attractive forces on extracellular ClÀ ions and reduced ClÀ entry into the pore at depolarized voltages. Login to comment
218 As a result, these direct effects show a strong dependence on side chain charge, being strongly disrupted in all mutants except R334K. Login to comment
226 Note the change in current rectification induced by extracellular Pt(NO2)4 2À in wild type, R334K, K95Q and R303Q but not other R334 mutants. Login to comment
228 ), R334E (5), R334H (j), R334K (), R334L (h), R334Q (u); c wild type (d), K95Q (m), R303Q (Å). Login to comment

PMID: 15130785 [PubMed] Gong X et al: "Maximization of the rate of chloride conduction in the CFTR channel pore by ion-ion interactions."

No. Sentence Comment

35 Results and discussion Previously we characterized the properties of six different R334 mutants (R334C, R334E, R334H, R334K, R334L, and R334Q) [19]. Login to comment
43 Each of these traces shows the activity of two active CFTR channels, except for R334K and R334W (one active channel). Login to comment
50 Comparison of unitary current amplitude at )100 mV showed that, compared to wild type, mean current was reduced by between 53 (in R334K) and 91% (in R334H) (Fig. 2B). Login to comment
65 (A) Unitary current-voltage relationships for each of the channel variants shown in Fig. 1: (d) wild type, (r) R334C, (j) R334E, (}) R334H, (s) R334K, () R334L, (.) Login to comment