ABCMdb

ABCC7 p.Gln1291Ala

ClinVar:	c.3872A>G , p.Gln1291Arg ? , not provided c.3871C>T , p.Gln1291* ? , not provided c.3873G>C , p.Gln1291His D , Pathogenic
CF databases:	c.3872A>G , p.Gln1291Arg (CFTR1) D , Q1291R, an A->G substitution at nucleotide position 4004 in exon 20 has a haplotype of 2-2-1 (KM19-D9-J44) with seven GATT repeats. The mutation creates a new BsaJI site.
Predicted by SNAP2:	A: D (95%), C: D (95%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: N (82%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), R: N (78%), 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: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, R: D, S: D, T: D, V: D, W: D, Y: D,

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Publications
[hide] Insight in eukaryotic ABC transporter function by ... FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19. Frelet A, Klein M
Insight in eukaryotic ABC transporter function by mutation analysis.
FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19., 2006-02-13 [PMID:16442101]

Abstract [show]
With regard to structure-function relations of ATP-binding cassette (ABC) transporters several intriguing questions are in the spotlight of active research: Why do functional ABC transporters possess two ATP binding and hydrolysis domains together with two ABC signatures and to what extent are the individual nucleotide-binding domains independent or interacting? Where is the substrate-binding site and how is ATP hydrolysis functionally coupled to the transport process itself? Although much progress has been made in the elucidation of the three-dimensional structures of ABC transporters in the last years by several crystallographic studies including novel models for the nucleotide hydrolysis and translocation catalysis, site-directed mutagenesis as well as the identification of natural mutations is still a major tool to evaluate effects of individual amino acids on the overall function of ABC transporters. Apart from alterations in characteristic sequence such as Walker A, Walker B and the ABC signature other parts of ABC proteins were subject to detailed mutagenesis studies including the substrate-binding site or the regulatory domain of CFTR. In this review, we will give a detailed overview of the mutation analysis reported for selected ABC transporters of the ABCB and ABCC subfamilies, namely HsCFTR/ABCC7, HsSUR/ABCC8,9, HsMRP1/ABCC1, HsMRP2/ABCC2, ScYCF1 and P-glycoprotein (Pgp)/MDR1/ABCB1 and their effects on the function of each protein.

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No. Sentence Comment
299 [137] Q493A, Q1291A, N505C, N1303K Q493A and N505C reduced and increased the frequency of CO, respectively. Login to comment
300 Q1291A decreased the effects of pyrophosphate without altering other functions. Login to comment

[hide] Mutations that change the position of the putative... J Biol Chem. 2002 Jan 18;277(3):2125-31. Berger AL, Ikuma M, Hunt JF, Thomas PJ, Welsh MJ
Mutations that change the position of the putative gamma-phosphate linker in the nucleotide binding domains of CFTR alter channel gating.
J Biol Chem. 2002 Jan 18;277(3):2125-31., 2002-01-18 [PMID:11788611]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel is an ATP-binding cassette transporter that contains conserved nucleotide-binding domains (NBDs). In CFTR, the NBDs bind and hydrolyze ATP to open and close the channel. Crystal structures of related NBDs suggest a structural model with an important signaling role for a gamma-phosphate linker peptide that couples bound nucleotide to movement of an alpha-helical subdomain. We mutated two residues in CFTR that the structural model predicts will uncouple effects of nucleotide binding from movement of the alpha-helical subdomain. These residues are Gln-493 and Gln-1291, which may directly connect the ATP gamma-phosphate to the gamma-phosphate linker, and residues Asn-505 and Asn-1303, which may form hydrogen bonds that stabilize the linker. In NBD1, Q493A reduced the frequency of channel opening, suggesting a role for this residue in coupling ATP binding to channel opening. In contrast, N505C increased the frequency of channel opening, consistent with a role for Asn-505 in stabilizing the inactive state of the NBD. In NBD2, Q1291A decreased the effects of pyrophosphate without altering other functions. Mutations of Asn-1303 decreased the rate of channel opening and closing, suggesting an important role for NBD2 in controlling channel burst duration. These findings are consistent with both the bacterial NBD structural model and gating models for CFTR. Our results extend models of nucleotide-induced structural changes from bacterial NBDs to a functional mammalian ATP-binding cassette transporter.

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Sentences [show]
No. Sentence Comment
6 In NBD2, Q1291A decreased the effects of pyrophosphate without altering other functions. Login to comment
79 Single-channel gating of wild type CFTR, CFTR-Q493A, and CFTR-Q1291A. Login to comment
80 A, examples of current from excised inside-out membrane patches containing single CFTR channels in the presence of 1 mM ATP and 75 nM PKA. Membrane potential was clamped at -80 mV. B, data from multiple patches. Asterisk indicates p Ͻ 0.05; n ϭ 7 for WT, n ϭ 4 for CFTR-Q493A, and n ϭ 3 for CFTR-Q1291A. Login to comment
94 Wild type CFTR, CFTR-Q493A, and CFTR-Q1291A had similar dose response curves for ATP-stimulated Cl- current. Login to comment
98 The apparent EC50 was 176 Ϯ 67 ␮M for wild type CFTR, 217 Ϯ 55 ␮M for CFTR-Q493A, and 159 Ϯ 70 ␮M for CFTR-Q1291A. Login to comment
101 Wild type CFTR, CFTR-Q493A, and CFTR-Q1291A showed similar cation requirements for Cl-channel activity. Login to comment
121 Wild type CFTR, CFTR-Q493A, and CFTR-Q1291A were all inhibited by ADP. Login to comment
122 A, examples of patches incubated with ATP (1 mM) and ADP (1 mM) during the times indicated. B, data from multiple patches show that wild type CFTR, CFTR-Q493A, and CFTR-Q1291A currents were inhibited by ADP to a similar extent. Login to comment
125 CFTR-Q1291A was stimulated only weakly by PPi. Login to comment
127 The membrane potential was clamped at -40 mV. Patches were incubated with 1 mM ATP and 4 mM PPi during the times indicated. B, data from multiple patches show that 4 mM PPi stimulated less Cl- current in CFTR-Q1291A (n ϭ 6) than in wild type CFTR (n ϭ 4) or CFTR-Q493A (n ϭ 4). Login to comment
142 Mutating Gln-1291 in NBD2 Reduced PPi Stimulation of CFTR Channel Activity-In contrast to the NBD1 Gln mutant, the NBD2 Gln variant Q1291A showed gating much like wild type (Fig. 2). Login to comment
146 Thus the normal burst duration in Q1291A suggests that mutation of the conserved Gln did not disrupt hydrolysis. Login to comment
147 Wild type CFTR and CFTR-Q1291A had the same apparent EC50 for ATP (Fig. 3) and the same response to variation of the divalent cation (Fig. 4). Login to comment
157 Despite the lack of effect of the Q1291A mutation on other aspects of gating, it dramatically reduced PPi stimulation (Fig. 6). Login to comment

[hide] Mutating the Conserved Q-loop Glutamine 1291 Selec... J Biol Chem. 2015 May 29;290(22):14140-53. doi: 10.1074/jbc.M114.611616. Epub 2015 Apr 17. Dong Q, Ernst SE, Ostedgaard LS, Shah VS, Ver Heul AR, Welsh MJ, Randak CO
Mutating the Conserved Q-loop Glutamine 1291 Selectively Disrupts Adenylate Kinase-dependent Channel Gating of the ATP-binding Cassette (ABC) Adenylate Kinase Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Reduces Channel Function in Primary Human Airway Epithelia.
J Biol Chem. 2015 May 29;290(22):14140-53. doi: 10.1074/jbc.M114.611616. Epub 2015 Apr 17., [PMID:25887396]

Abstract [show]
The ATP-binding cassette (ABC) transporter cystic fibrosis transmembrane conductance regulator (CFTR) and two other non-membrane-bound ABC proteins, Rad50 and a structural maintenance of chromosome (SMC) protein, exhibit adenylate kinase activity in the presence of physiologic concentrations of ATP and AMP or ADP (ATP + AMP left arrow over right arrow 2 ADP). The crystal structure of the nucleotide-binding domain of an SMC protein in complex with the adenylate kinase bisubstrate inhibitor P(1),P(5)-di(adenosine-5') pentaphosphate (Ap5A) suggests that AMP binds to the conserved Q-loop glutamine during the adenylate kinase reaction. Therefore, we hypothesized that mutating the corresponding residue in CFTR, Gln-1291, selectively disrupts adenylate kinase-dependent channel gating at physiologic nucleotide concentrations. We found that substituting Gln-1291 with bulky side-chain amino acids abolished the effects of Ap5A, AMP, and adenosine 5'-monophosphoramidate on CFTR channel function. 8-Azidoadenosine 5'-monophosphate photolabeling of the AMP-binding site and adenylate kinase activity were disrupted in Q1291F CFTR. The Gln-1291 mutations did not alter the potency of ATP at stimulating current or ATP-dependent gating when ATP was the only nucleotide present. However, when physiologic concentrations of ADP and AMP were added, adenylate kinase-deficient Q1291F channels opened significantly less than wild type. Consistent with this result, we found that Q1291F CFTR displayed significantly reduced Cl(-) channel function in well differentiated primary human airway epithelia. These results indicate that a highly conserved residue of an ABC transporter plays an important role in adenylate kinase-dependent CFTR gating. Furthermore, the results suggest that adenylate kinase activity is important for normal CFTR channel function in airway epithelia.

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Sentences [show]
No. Sentence Comment
142 Gln mutations that resulted in shortening (Q1291A) or deletion (Q1291G) of the side chain reduced Ap5A inhibition (Fig. 3, A FIGURE 1. Login to comment
181 No significant differences were detected between bars 1, 3, 4, 5, 6, 7, and 8 (one-way ANOVA followed by Holm-Sidak`s method of all pairwise multiple comparisons; wild-type CFTR, n afd; 13; F508del CFTR, n afd; 10; Q1291A CFTR, n afd; 4; Q1291G CFTR, n afd; 4; Q1291F CFTR, n afd; 6; Q1291H CFTR, n afd; 6; Q1291W CFTR, n afd; 6; Q1291Y CFTR, n afd; 6). Login to comment
224 Consistent with our findings, a previous study showed that the Q1291A mutation did not change burst duration, interburst interval, or the ATP dose-response curve (52). Login to comment