ABCC7 p.Arg553Cys
| ClinVar: |
c.1657C>T
,
p.Arg553*
D
, Pathogenic
c.1657C>G , p.Arg553Gly ? , not provided c.1658G>A , p.Arg553Gln D , Pathogenic |
| CF databases: |
c.1657C>T
,
p.Arg553*
D
, CF-causing
c.1657C>G , p.Arg553Gly (CFTR1) ? , This mutation was found identified by DGGE and direct sequencing. This nucleotide change was observe in a French CF chromosome. c.1658G>A , p.Arg553Gln (CFTR1) ? , The amino acid change was found in a German CF patient on the maternal [delta]F508 CF chromosome associated with the haplotype 1-2-1-1-1-2 in J3.11(Msp) - KM.19 (Pst) - XV-2c - metH(Msp) - metH (Taq) - metD(taq). The paternal CF chromosome carries the 553X Stop mutation. So far, the R553Q mutation was not found on a small number of normal and of CF [delta]F508 or non-[delta]F508 chromosomes. Since this mutation occurs in the region of sequence identity with other membrane-associated proteins or transport systems that may contain glutamine instead of a basic amino acid at this position, we assume that this mutation may be neither a polymorphism nor may cayse disease but rather modulates the function of the [delta]F508 CFTR gene product. |
| Predicted by SNAP2: | A: D (95%), C: D (95%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: D (95%), I: D (95%), K: D (85%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), Q: D (59%), S: D (95%), T: D (95%), V: D (95%), W: D (95%), Y: D (95%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: N, F: D, G: D, H: D, I: D, K: N, L: D, M: D, N: D, P: D, Q: N, S: D, T: D, V: D, W: D, Y: D, |
[switch to compact view]
Comments [show]
None has been submitted yet.
[hide] Mutations at the signature sequence of CFTR create... J Gen Physiol. 2009 Jan;133(1):69-77. Wang X, Bompadre SG, Li M, Hwang TC
Mutations at the signature sequence of CFTR create a Cd(2+)-gated chloride channel.
J Gen Physiol. 2009 Jan;133(1):69-77., [PMID:19114635]
Abstract [show]
The canonical sequence LSGGQ, also known as the signature sequence, defines the adenosine triphosphate (ATP)-binding cassette transporter superfamily. Crystallographic studies reveal that the signature sequence, together with the Walker A and Walker B motifs, forms the ATP-binding pocket upon dimerization of the two nucleotide-binding domains (NBDs) in a head-to-tail configuration. The importance of the signature sequence is attested by the fact that a glycine to aspartate mutation (i.e., G551D) in cystic fibrosis transmembrane conductance regulator (CFTR) results in a severe phenotype of cystic fibrosis. We previously showed that the G551D mutation completely eliminates ATP-dependent gating of the CFTR chloride channel. Here, we report that micromolar [Cd(2+)] can dramatically increase the activity of G551D-CFTR in the absence of ATP. This effect of Cd(2+) is not seen in wild-type channels or in G551A. Pretreatment of G551D-CFTR with the cysteine modification reagent 2-aminoethyl methane thiosulfonate hydrobromide protects the channel from Cd(2+) activation, suggesting an involvement of endogenous cysteine residue(s) in mediating this effect of Cd(2+). The mutants G551C, L548C, and S549C, all in the signature sequence of CFTR's NBD1, show robust response to Cd(2+). On the other hand, negligible effects of Cd(2+) were seen with T547C, Q552C, and R553C, indicating that a specific region of the signature sequence is involved in transmitting the signal of Cd(2+) binding to the gate. Collectively, these results suggest that the effect of Cd(2+) is mediated by a metal bridge formation between yet to be identified cysteine residue(s) and the engineered aspartate or cysteine in the signature sequence. We propose that the signature sequence serves as a switch that transduces the signal of ligand binding to the channel gate.
Comments [show]
None has been submitted yet.
No. Sentence Comment
23 On the other hand, negligible effects of Cd2+ were seen with T547C, Q552C, and R553C, indicating that a specific region of the signature sequence is involved in transmitting the signal of Cd2+ binding to the gate.
X
ABCC7 p.Arg553Cys 19114635:23:79
status: NEW106 It appears that when cysteine is engineered outside the signature sequence (i.e., T547C and R553C) or at the C-terminal end of the signature sequence (i.e., Q552C), ATP remains a much better ligand than Cd2+ (e.g., Fig. 6 B).
X
ABCC7 p.Arg553Cys 19114635:106:92
status: NEW168 Fig. 6 demonstrates that the Cd2+ -dependent gating also involves the signature sequence because engineering cysteine residues framing the signature sequence (i.e., T547C and R553C) did not confer this effect of Cd2+ .
X
ABCC7 p.Arg553Cys 19114635:168:175
status: NEW