ABCC7 p.Pro99Ala
ClinVar: |
c.296C>T
,
p.Pro99Leu
?
, not provided
|
CF databases: |
c.296C>T
,
p.Pro99Leu
(CFTR1)
?
, This mutation was found together with [delta]F508 in a patient with extreme mild symptoms. It was found by SSCP and sequencing.
|
Predicted by SNAP2: | A: D (85%), C: D (85%), D: D (80%), E: D (95%), F: D (91%), G: D (91%), H: D (91%), I: D (91%), K: D (95%), L: D (91%), M: D (91%), N: D (91%), Q: D (91%), R: D (95%), S: D (85%), T: D (85%), V: D (91%), W: D (95%), Y: D (91%), |
Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] Direct comparison of the functional roles played b... J Biol Chem. 2004 Dec 31;279(53):55283-9. Epub 2004 Oct 25. Ge N, Muise CN, Gong X, Linsdell P
Direct comparison of the functional roles played by different transmembrane regions in the cystic fibrosis transmembrane conductance regulator chloride channel pore.
J Biol Chem. 2004 Dec 31;279(53):55283-9. Epub 2004 Oct 25., 2004-12-31 [PMID:15504721]
Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel contains 12 transmembrane (TM) regions that are presumed to form the channel pore. However, little is known about the relative functional contribution of different TM regions to the pore. We have used patch clamp recording to investigate the functional consequences of point mutations throughout the six transmembrane regions in the N-terminal part of the CFTR protein (TM1-TM6). A range of specific functional assays compared the single channel conductance, anion binding, and anion selectivity properties of different channel variants. Overall, our results suggest that TM1 and -6 play dominant roles in forming the channel pore and determining its functional properties, with TM5 perhaps playing a lesser role. In contrast, TM2, -3, and -4 appear to play only minor supporting roles. These results define transmembrane regions 1 and 6 as major contributors to the CFTR channel pore and have strong implications for emerging structural models of CFTR and related ATP-binding cassette proteins.
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No. Sentence Comment
76 However, the unitary conductance was drastically reduced by some mutations in TM1 (K95Q, Q98A, P99A) and TM6 (R334K, F337A) (Figs. 2-4).
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ABCC7 p.Pro99Ala 15504721:76:95
status: NEW82 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.
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ABCC7 p.Pro99Ala 15504721:82:242
status: NEW[hide] Structure and function of the CFTR chloride channe... Physiol Rev. 1999 Jan;79(1 Suppl):S23-45. Sheppard DN, Welsh MJ
Structure and function of the CFTR chloride channel.
Physiol Rev. 1999 Jan;79(1 Suppl):S23-45., [PMID:9922375]
Abstract [show]
Structure and Function of the CFTR Chloride Channel. Physiol. Rev. 79, Suppl.: S23-S45, 1999. - The cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ABC transporter family that forms a novel Cl- channel. It is located predominantly in the apical membrane of epithelia where it mediates transepithelial salt and liquid movement. Dysfunction of CFTR causes the genetic disease cystic fibrosis. The CFTR is composed of five domains: two membrane-spanning domains (MSDs), two nucleotide-binding domains (NBDs), and a regulatory (R) domain. Here we review the structure and function of this unique channel, with a focus on how the various domains contribute to channel function. The MSDs form the channel pore, phosphorylation of the R domain determines channel activity, and ATP hydrolysis by the NBDs controls channel gating. Current knowledge of CFTR structure and function may help us understand better its mechanism of action, its role in electrolyte transport, its dysfunction in cystic fibrosis, and its relationship to other ABC transporters.
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No. Sentence Comment
124 When the basic arginine at this position was re- gle-channel Cl0 conductance in the rank order: wild type ' P99G ú P99L ' P99A (119).
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ABCC7 p.Pro99Ala 9922375:124:127
status: NEW[hide] Contribution of proline residues in the membrane-s... J Biol Chem. 1996 Jun 21;271(25):14995-5001. Sheppard DN, Travis SM, Ishihara H, Welsh MJ
Contribution of proline residues in the membrane-spanning domains of cystic fibrosis transmembrane conductance regulator to chloride channel function.
J Biol Chem. 1996 Jun 21;271(25):14995-5001., [PMID:8663008]
Abstract [show]
Proline residues located in membrane-spanning domains of transport proteins are thought to play an important structural role. In the cystic fibrosis transmembrane conductance regulator (CFTR), the predicted transmembrane segments contain four prolines: Pro99, Pro205, Pro324, and Pro1021. These residues are conserved across species, and mutations of two (P99L and P205S) are associated with cystic fibrosis. To evaluate the contribution of these prolines to CFTR Cl- channel function, we mutated each residue individually to either alanine or glycine or mutated all four simultaneously to alanine (P-Quad-A). We also constructed the two cystic fibrosis-associated mutations. cAMP agonists stimulated whole cell Cl- currents in HeLa cells expressing the individual constructs that resembled those produced by wild-type CFTR. However, the amount of current was decreased in the rank order: wild-type CFTR = Pro324 > Pro1021 > Pro99 >/= Pro205 mutants. The anion selectivity sequence of the mutants (Br- >/= Cl- > I-) resembled wild-type except for P99L (Br- >/= Cl- = I-). Although the Pro99, Pro324, and Pro1021 mutants produced mature protein, the amount of mature protein was much reduced with the Pro205 mutants, and the P-Quad-A made none. Because the Pro99 constructs produced mature protein but had altered whole cell currents, we investigated their single-channel properties. Mutant channels were regulated like wild-type CFTR; however, single-channel conductance was decreased in the rank order: wild-type CFTR >/= P99G > P99L >/= P99A. These results suggest that proline residues in the transmembrane segments are important for CFTR function, Pro205 is critical for correct protein processing, and Pro99 may contribute either directly or indirectly to the Cl- channel pore.
Comments [show]
None has been submitted yet.
No. Sentence Comment
9 Mutant channels were regulated like wild-type CFTR; however, single-channel conductance was decreased in the rank order: wild-type CFTR P99G > P99L P99A.
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ABCC7 p.Pro99Ala 8663008:9:148
status: NEW77 As an example, Fig. 2 shows data from studies of P99A, P99G, and P99L; qualitatively similar results were obtained with the Pro205 , Pro324 , and Pro1021 mutants (data not shown).
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ABCC7 p.Pro99Ala 8663008:77:49
status: NEW119 Reversal potentials (Erev) of baseline subtracted cAMP-activated whole cell currents were P99A, -30 Ϯ 1 mV (n ϭ 7); P99G, -34 Ϯ 2 mV (n ϭ 5); and P99L, -24 Ϯ 3 mV (n ϭ 6).
X
ABCC7 p.Pro99Ala 8663008:119:90
status: NEW122 Mutant n Px/PCl Gx/GCl Br- Cl- IBr- ClI- CFTR 5 1.18 Ϯ 0.08 1.00 0.73 Ϯ 0.05 1.27 Ϯ 0.16 1.00 0.61 Ϯ 0.08 P99A 7 0.98 Ϯ 0.03 1.00 0.70 Ϯ 0.06 1.04 Ϯ 0.05 1.00 0.72 Ϯ 0.05 P99G 5 1.06 Ϯ 0.02 1.00 0.75 Ϯ 0.08 1.04 Ϯ 0.07 1.00 0.66 Ϯ 0.05 P99L 5 1.21 Ϯ 0.07 1.00 1.06 Ϯ 0.07 1.33 Ϯ 0.11 1.00 0.95 Ϯ 0.08 P205A 4 1.09 Ϯ 0.07 1.00 0.64 Ϯ 0.09 0.95 Ϯ 0.04 1.00 0.46 Ϯ 0.11 P205G 5 1.09 Ϯ 0.05 1.00 0.45 Ϯ 0.05 1.05 Ϯ 0.03 1.00 0.44 Ϯ 0.06 P205S 2 1.01 Ϯ 0.01 1.00 0.55 Ϯ 0.28 1.09 Ϯ 0.09 1.00 0.59 Ϯ 0.08 P324A 7 1.08 Ϯ 0.04 1.00 0.72 Ϯ 0.06 1.15 Ϯ 0.07 1.00 0.60 Ϯ 0.08 P324G 6 1.12 Ϯ 0.07 1.00 0.69 Ϯ 0.04 1.22 Ϯ 0.14 1.00 0.57 Ϯ 0.04 P1021A 3 1.15 Ϯ 0.17 1.00 0.73 Ϯ 0.11 1.17 Ϯ 0.10 1.00 0.47 Ϯ 0.19 P1021G 7 1.17 Ϯ 0.06 1.00 0.78 Ϯ 0.02 1.21 Ϯ 0.08 1.00 0.59 Ϯ 0.06 though for P99G the reduction was small, for P99A and P99L the effect was marked.
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ABCC7 p.Pro99Ala 8663008:122:130
status: NEWX
ABCC7 p.Pro99Ala 8663008:122:1075
status: NEW126 The conductance for P99G was 7.31 Ϯ 0.24 pS (n ϭ 5), not significantly different from wild type (p ϭ 0.26).
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ABCC7 p.Pro99Ala 8663008:126:110
status: NEWX
ABCC7 p.Pro99Ala 8663008:126:815
status: NEW127 In contrast, the conductances of P99A and P99L were significantly decreased at 4.66 Ϯ 0.25 pS (n ϭ 5, p Ͻ 0.0001) and 4.97 Ϯ 0.24 pS (n ϭ 5, p Ͻ 0.0001), respectively.
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ABCC7 p.Pro99Ala 8663008:127:33
status: NEW129 Because the single-channel current amplitudes of P99A and P99L were much reduced and because in most cases the patches of membrane contained large numbers of channels, we could not accurately measure single-channel kinetics.
X
ABCC7 p.Pro99Ala 8663008:129:49
status: NEW145 The number of cells responding to cAMP agonists with Cl- current activation relative to the total number of cells tested for each construct was: CFTR (8/16; 50%), P99A (11/12; 92%), P99G (9/19; 47%), P99L (10/19; 53%), P205A (7/12; 58%), P205G (5/9; 56%), P205S (7/20; 35%), P324A (9/18; 50%), P324G (9/22; 41%), P1021A (8/18; 44%), and P1021G (7/16; 44%).
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ABCC7 p.Pro99Ala 8663008:145:163
status: NEW172 A, regulation of P99A by phosphorylation with the catalytic subunit of cAMP-dependent protein kinase (75 nM) and intracellular MgATP (0.88 mM).
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ABCC7 p.Pro99Ala 8663008:172:17
status: NEW173 Representative recording are from an excised inside-out membrane patch from a HeLa cell transiently expressing P99A.
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ABCC7 p.Pro99Ala 8663008:173:111
status: NEW177 B, representative single-channel recordings are from excised inside-out membrane patches from HeLa cells transiently expressing wild-type CFTR, P99A, P99G, and P99L.
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ABCC7 p.Pro99Ala 8663008:177:17
status: NEWX
ABCC7 p.Pro99Ala 8663008:177:144
status: NEW180 C, single-channel I-V relationships of CFTR (circles), P99A (squares), P99G (triangles), and P99L (inverted triangles.
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ABCC7 p.Pro99Ala 8663008:180:55
status: NEW199 Substitution of alanine, glycine, and leucine at Pro99 decreased single-channel conductance in the rank order: wild-type CFTR Ն P99G Ͼ P99L Ն P99A.
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ABCC7 p.Pro99Ala 8663008:199:160
status: NEW206 Implications for Cystic Fibrosis-P99L and P205S are CF mutations located in MSD1 that are associated with a milder (pancreatic sufficiency) clinical phenotype (12, 13).
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ABCC7 p.Pro99Ala 8663008:206:7
status: NEW78 As an example, Fig. 2 shows data from studies of P99A, P99G, and P99L; qualitatively similar results were obtained with the Pro205 , Pro324 , and Pro1021 mutants (data not shown).
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ABCC7 p.Pro99Ala 8663008:78:49
status: NEW123 Reversal potentials (Erev) of baseline subtracted cAMP-activated whole cell currents were P99A, 230 6 1 mV (n 5 7); P99G, 234 6 2 mV (n 5 5); and P99L, 224 6 3 mV (n 5 6).
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ABCC7 p.Pro99Ala 8663008:123:90
status: NEW131 In contrast, the conductances of P99A and P99L were significantly decreased at 4.66 6 0.25 pS (n 5 5, p , 0.0001) and 4.97 6 0.24 pS (n 5 5, p , 0.0001), respectively.
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ABCC7 p.Pro99Ala 8663008:131:33
status: NEW133 Because the single-channel current amplitudes of P99A and P99L were much reduced and because in most cases the patches of membrane contained large numbers of channels, we could not accurately measure single-channel kinetics.
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ABCC7 p.Pro99Ala 8663008:133:49
status: NEW149 The number of cells responding to cAMP agonists with Cl2 current activation relative to the total number of cells tested for each construct was: CFTR (8/16; 50%), P99A (11/12; 92%), P99G (9/19; 47%), P99L (10/19; 53%), P205A (7/12; 58%), P205G (5/9; 56%), P205S (7/20; 35%), P324A (9/18; 50%), P324G (9/22; 41%), P1021A (8/18; 44%), and P1021G (7/16; 44%).
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ABCC7 p.Pro99Ala 8663008:149:163
status: NEW178 Representative recording are from an excised inside-out membrane patch from a HeLa cell transiently expressing P99A.
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ABCC7 p.Pro99Ala 8663008:178:111
status: NEW183 B, representative single-channel recordings are from excised inside-out membrane patches from HeLa cells transiently expressing wild-type CFTR, P99A, P99G, and P99L.
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ABCC7 p.Pro99Ala 8663008:183:144
status: NEW186 C, single-channel I-V relationships of CFTR (circles), P99A (squares), P99G (triangles), and P99L (inverted triangles.
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ABCC7 p.Pro99Ala 8663008:186:55
status: NEW