ABCMdb

ABCC7 p.Ser341Lys

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Publications

PMID: 20142516 [PubMed] Zhou JJ et al: "Regulation of conductance by the number of fixed positive charges in the intracellular vestibule of the CFTR chloride channel pore."

No. Sentence Comment

62 Fig. S1 shows the inhibitory effects of TLCS and lonidamine on wild type, K95S, K95S/S341K, and K95S/S1141K-CFTR. Login to comment
63 Fig. S2 shows single-channel recordings of K95S/S341K and S341K. Login to comment
66 Fig. S5 shows the block of wild type, S1141K, and S341K by intracellular NPPB. Login to comment
76 In a K95S background, the introduction of a positive charge in either TM6 (S341K) or TM12 (S1141K) led to a significant increase in the apparent potency of NPPB block compared with K95S alone (Fig. 1), with mean Kd(0) values of 35.8 ± 2.0 µM (n = 4) in K95S/S341K and 10.5 ± 1.8 µM (n = 4) in K95S/S1141K (Fig. 1 D), again with no significant change in apparent voltage dependence of block (z of 0.17 ± 0.02 [n = 4] in K95S/ S341K and 0.22 ± 0.03 [n = 4] in K95S/S1141K). Login to comment
106 , wild type (B); , K95S (B and C); , K95S/S341K (C); , K95S/S1141K (C). Login to comment
107 Each set of data has been fit by Eq. 1, giving for wild-type: Kd(0) = 12.3 ± 0.1 µM and z = 0.20 ± 0.01; for K95S: Kd(0) = 83.9 ± 0.6 µM and z = 0.16 ± 0.00; for K95S/S341K: Kd(0) = 33.7 ± 0.7 µM and z = 0.15 ± 0.01; and for K95S/S1141K: Kd(0) = 10.3 ± 0.1 µM and z = 0.22 ± 0.01. Login to comment
127 Thus, the S341K mutant was associated with very small unitary currents that were difficult to resolve unequivocally when introduced into either a wild-type or a K95S background (Fig. S2). Login to comment
184 None of these effects was observed in wild type or K95S/S1141K, two channel variants with a single positive charge in this part of the inner vestibule of the pore (Fig. 5), or in S341K (not depicted). Login to comment
248 The ability of a positive charge located in TM1 (K95), TM6 (S341K), or TM12 (S1141K) to support blocker interactions is consistent with each of these TMs influencing the movement of blocking anions in the pore. Login to comment
267 Thus, both S341K and K95S/S341K were associated with very low single-channel conductance (Fig. S2). Login to comment
291 Interestingly, in all cases, blocker apparent valence was not significantly different between wild type and double mutants showing restored blocker binding (K95S/S341K, K95S/S1141K), suggesting that blocker movement in the TM electric field was well conserved in these mutants. Login to comment

PMID: 23083715 [PubMed] El Hiani Y et al: "Tuning of CFTR chloride channel function by location of positive charges within the pore."

No. Sentence Comment

57 Similar results were previously reported for NPPB block of K95S/S341K and K95S/S1141K (8). Login to comment
60 As shown in Fig. 4, block by Pt(NO2)4 2 was significantly strengthened in each of the mutants Q98K, I344K, V345K, M348K, and A349K, as well as in the previously unstudied S341K. Login to comment
61 At 0 mV membrane potential, the apparent Kd for Pt(NO2)4 2 block was in the rank order V345K (3.3 5 0.9 mM, n &#bc; 7) % I344K (4.5 5 0.7 mM, n &#bc; 6) < S341K (26.6 5 1.8 mM, n &#bc; 7) < M348K (80.9 5 7.2 mM, n &#bc; 5) % Q98K (95.4 5 11.0 mM, n &#bc; 6) % A349K (117.4 5 7.7 mM, FIGURE 2 Single-channel conductance is restored by moving the positive charge from K95. Login to comment
86 Only S341K, located more deeply in the pore from its cytoplasmic end, was unable to support high conductance (8). Login to comment
146 Again this appears to be a relatively nonsite-specific effect of positive charge, since all mutants studied (Q98K, S341K, I344K, V345K, M348K, and A349K) led to significant increase in apparent affinity of Pt(NO2)4 2 block (Fig. 4), as did S1141K (8). Login to comment
157 At the outermost extent of this inner pore region, the open-channel pore may become too narrow to accommodate a positive charge (as previously proposed to explain the low single-channel conductance of S341K and other mutations at the same site (8)). Login to comment