ABCC7 p.Lys1060Cys
ClinVar: |
c.3179A>C
,
p.Lys1060Thr
?
, not provided
|
CF databases: |
c.3179A>C
,
p.Lys1060Thr
(CFTR1)
D
, This mutation was detected by DGGE analysis and identified by direct sequencing. This mutation was found in one Spanish man with CBAVD.
|
Predicted by SNAP2: | A: N (53%), C: N (61%), D: D (71%), E: D (59%), F: D (66%), G: D (59%), H: N (66%), I: N (53%), L: D (53%), M: N (53%), N: D (53%), P: D (71%), Q: N (87%), R: N (87%), S: D (53%), T: N (57%), V: D (53%), W: D (71%), Y: D (53%), |
Predicted by PROVEAN: | A: N, C: D, D: N, E: N, F: D, G: N, H: N, I: D, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: N, |
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[hide] An electrostatic interaction at the tetrahelix bun... J Biol Chem. 2014 Oct 31;289(44):30364-78. doi: 10.1074/jbc.M114.595710. Epub 2014 Sep 4. Wang W, Roessler BC, Kirk KL
An electrostatic interaction at the tetrahelix bundle promotes phosphorylation-dependent cystic fibrosis transmembrane conductance regulator (CFTR) channel opening.
J Biol Chem. 2014 Oct 31;289(44):30364-78. doi: 10.1074/jbc.M114.595710. Epub 2014 Sep 4., [PMID:25190805]
Abstract [show]
The CFTR channel is an essential mediator of electrolyte transport across epithelial tissues. CFTR opening is promoted by ATP binding and dimerization of its two nucleotide binding domains (NBDs). Phosphorylation of its R domain (e.g. by PKA) is also required for channel activity. The CFTR structure is unsolved but homology models of the CFTR closed and open states have been produced based on the crystal structures of evolutionarily related ABC transporters. These models predict the formation of a tetrahelix bundle of intracellular loops (ICLs) during channel opening. Here we provide evidence that residues E267 in ICL2 and K1060 in ICL4 electrostatically interact at the interface of this predicted bundle to promote CFTR opening. Mutations or a thiol modifier that introduced like charges at these two positions substantially inhibited ATP-dependent channel opening. ATP-dependent activity was rescued by introducing a second site gain of function (GOF) mutation that was previously shown to promote ATP-dependent and ATP-independent opening (K978C). Conversely, the ATP-independent activity of the K978C GOF mutant was inhibited by charge- reversal mutations at positions 267 or 1060 either in the presence or absence of NBD2. The latter result indicates that this electrostatic interaction also promotes unliganded channel opening in the absence of ATP binding and NBD dimerization. Charge-reversal mutations at either position markedly reduced the PKA sensitivity of channel activation implying strong allosteric coupling between bundle formation and R domain phosphorylation. These findings support important roles of the tetrahelix bundle and the E267-K1060 electrostatic interaction in phosphorylation-dependent CFTR gating.
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No. Sentence Comment
127 As we showed in Fig. 2 the single E267C and K1060C mutations reduced CFTR channel activity especially after PKI addition but not to the extent of the charge-reversal substitutions.
X
ABCC7 p.Lys1060Cys 25190805:127:44
status: NEW129 Conversely, the same positively charged reagent modestly increased the current mediated by K1060C-CFTR; an effect that also was reversed by DTT (Fig. 4B; mean data in Fig. 4C).
X
ABCC7 p.Lys1060Cys 25190805:129:91
status: NEW212 A positively charged thiol modifier strongly inhibits E267C-CFTR currents in an activity-dependent manner but modestly stimulates K1060C-CFTR currents.
X
ABCC7 p.Lys1060Cys 25190805:212:130
status: NEW215 B, corresponding K1060C-CFTR macropatch record showing modest stimulation of this cysteine mutant by MTSET that also was reversed by subsequent DTT addition.
X
ABCC7 p.Lys1060Cys 25190805:215:17
status: NEW