ABCC7 p.Asn1303Ala
| ClinVar: |
c.3908A>T
,
p.Asn1303Ile
?
, not provided
c.3909C>G , p.Asn1303Lys D , Pathogenic c.3907A>C , p.Asn1303His D , Pathogenic |
| CF databases: |
c.3909C>G
,
p.Asn1303Lys
D
, CF-causing ; CFTR1: The substitution was found in three adult British Caucasian patients all of whom are heterozygous for the mutation. Two of the patients are pancreatic sufficient with mild to moderate lung disease, and their other chromosomes carry an, as yet, uncharacterized mutation. In all patients the substitution appears to be associated with the haplotype 1,2,2 at XV-2C, KM19 and pMP6d-9 respectively. The third patient has the 551 mutation on the other chromosome, is pancreatic insufficient and died in respiratory failure at the age of 22.
c.3907A>C , p.Asn1303His (CFTR1) ? , The mutation can be detected by ASO hybridization (normal: 5'-TAG AAA AAA CTTGGA-3'; mutant: 5'-TAG AAA ACA CTT GGA-3'). The patient is 22 years old and is originating from the Kabilie ethnic group (North Africa); he presents a severe disease, including hepatic and exocrine pancreatic insufficiencies. c.3908A>T , p.Asn1303Ile (CFTR1) ? , |
| Predicted by SNAP2: | A: D (95%), C: D (95%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: N (78%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), P: D (95%), Q: D (95%), R: D (95%), 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, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[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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No. Sentence Comment
161 We observed similar kinetic effects when Asn-1303 was changed to another CF-associated mutation (N1303H), a sequenced mutation with undetermined clinical consequences (N1303I), and an Ala (N1303A) (Fig. 8).
X
ABCC7 p.Asn1303Ala 11788611:161:189
status: NEW171 However, in contrast to the reduced EC50 for ATP observed for mutations at Lys-1250 (21), the apparent EC50 for CFTR-N1303A (253 Ϯ 62 M, n ϭ 5) was not different from that of wild type CFTR (176 Ϯ 67 M, n ϭ 5).
X
ABCC7 p.Asn1303Ala 11788611:171:117
status: NEW180 Comparison of single-channel kinetics of CFTR-N1303K, CFTR-N1303H, CFTR-N1303I, and CFTR-N1303A.
X
ABCC7 p.Asn1303Ala 11788611:180:89
status: NEW[hide] An intrinsic adenylate kinase activity regulates g... Cell. 2003 Dec 26;115(7):837-50. Randak C, Welsh MJ
An intrinsic adenylate kinase activity regulates gating of the ABC transporter CFTR.
Cell. 2003 Dec 26;115(7):837-50., [PMID:14697202]
Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel in the ATP binding cassette (ABC) transporter family. Like other ABC transporters, it can hydrolyze ATP. Yet while ATP hydrolysis influences channel gating, it has long seemed puzzling that CFTR would require this reaction because anions flow passively through CFTR. Moreover, no other ion channel is known to require the large energy of ATP hydrolysis to gate. We found that CFTR also has adenylate kinase activity (ATP + AMP <=> ADP + ADP) that regulates gating. When functioning as an adenylate kinase, CFTR showed positive cooperativity for ATP suggesting its two nucleotide binding domains may dimerize. Thus, channel activity could be regulated by two different enzymatic reactions, ATPase and adenylate kinase, that share a common ATP binding site in the second nucleotide binding domain. At physiologic nucleotide concentrations, adenylate kinase activity, rather than ATPase activity may control gating, and therefore involve little energy consumption.
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No. Sentence Comment
262 We also made the corresponding mutations in CFTR of ATP, and agrees with our earlier finding that wild-type and N1303A CFTR had the same ATP EC50 for current and examined their effect on channel activity.
X
ABCC7 p.Asn1303Ala 14697202:262:112
status: NEW