ABCC7 p.Glu543Cys
| Predicted by SNAP2: | A: D (85%), C: D (80%), D: N (61%), F: D (91%), G: D (91%), H: D (91%), I: D (91%), K: D (91%), L: D (91%), M: D (85%), N: D (91%), P: D (95%), Q: D (85%), R: D (95%), S: D (85%), T: D (91%), V: D (85%), W: D (91%), Y: D (91%), |
| Predicted by PROVEAN: | A: D, C: D, D: N, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] Multiple membrane-cytoplasmic domain contacts in t... J Biol Chem. 2008 Sep 26;283(39):26383-90. Epub 2008 Jul 25. He L, Aleksandrov AA, Serohijos AW, Hegedus T, Aleksandrov LA, Cui L, Dokholyan NV, Riordan JR
Multiple membrane-cytoplasmic domain contacts in the cystic fibrosis transmembrane conductance regulator (CFTR) mediate regulation of channel gating.
J Biol Chem. 2008 Sep 26;283(39):26383-90. Epub 2008 Jul 25., 2008-09-26 [PMID:18658148]
Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) is a unique ATP-binding cassette (ABC) ion channel mutated in patients with cystic fibrosis. The most common mutation, deletion of phenylalanine 508 (DeltaF508) and many other disease-associated mutations occur in the nucleotide binding domains (NBD) and the cytoplasmic loops (CL) of the membrane-spanning domains (MSD). A recently constructed computational model of the CFTR three-dimensional structure, supported by experimental data (Serohijos, A. W., Hegedus, T., Aleksandrov, A. A., He, L., Cui, L., Dokholyan, N. V., and Riordan, J. R. (2008) Proc. Natl. Acad. Sci. U. S. A. 105, 3256-3261) revealed that several of these mutations including DeltaF508 disrupted interfaces between these domains. Here we have used cysteine cross-linking experiments to verify all NBD/CL interfaces predicted by the structural model and observed that their cross-linking has a variety of different effects on channel gating. The interdomain contacts comprise aromatic clusters important for stabilization of the interfaces and also involve the Q-loops and X-loops that are in close proximity to the ATP binding sites. Cross-linking of all domain-swapping contacts between NBDs and MSD cytoplasmic loops in opposite halves of the protein rapidly and reversibly arrest single channel gating while those in the same halves have lesser impact. These results reinforce the idea that mediation of regulatory signals between cytoplasmic- and membrane-integrated domains of the CFTR channel apparently relies on an array of precise but highly dynamic interdomain structural joints.
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No. Sentence Comment
90 Cys pair cross-linking experiments showed that indeed E543C could be cross-linked with both T966C (CL3) and T1057C (CL4, Fig. 2B), while D1341C was in close contact with both L172C (CL1) and N268C (CL2, Fig. 2C).
X
ABCC7 p.Glu543Cys 18658148:90:54
status: NEW101 B, T966C/E543C at the CL3/NBD1 interface and T1057C/E543C at the CL4/NBD1 interface at the X-loop of NBD1.
X
ABCC7 p.Glu543Cys 18658148:101:9
status: NEWX
ABCC7 p.Glu543Cys 18658148:101:52
status: NEW127 No cross-linking was detected when Cys pairs were introduced at L172C/E543C, T966C/D1341C, V171C/L1261C, or M961C/L408C, which are not predicted to be in association in the structural model (supplemental Fig. S3).
X
ABCC7 p.Glu543Cys 18658148:127:70
status: NEW142 To determine whether the interfacial interaction of Glu-543 with CL3 and CL4 was indeed affected by PKA phosphorylation, membrane vesicles from HEK cells overexpressing Cys-less CFTR with Cys pairs E543C/T966C and E543C/T1057C were pretreated with PKA in the presence of ATP and Mg2ϩ before cross-linking with various MTS reagents.
X
ABCC7 p.Glu543Cys 18658148:142:198
status: NEWX
ABCC7 p.Glu543Cys 18658148:142:214
status: NEW143 As shown in Fig. 4A, similar to the experiments with whole cells in membranes not treated with PKA, the Cys pairs E543C/T966C and E543C/T1057C were cross-linked by all the MTS reagents tested.
X
ABCC7 p.Glu543Cys 18658148:143:114
status: NEWX
ABCC7 p.Glu543Cys 18658148:143:130
status: NEW159 Membrane vesicles prepared from HEK cells transiently transfected with Cys pairs introduced at E543C with T966C (CL3) and T1064C (CL4) were pretreated with PKA catalytic subunit in the presence of ATP before incubating with 20 M MTS reagents.
X
ABCC7 p.Glu543Cys 18658148:159:95
status: NEW170 In contrast, the cross-linking between residues T996C and E543C at the CL3/NBD1 interface rapidly and reversibly arrested channel gating (Fig. 6B) exactly as we had observed previously with the CL4/NBD1 interface (19).
X
ABCC7 p.Glu543Cys 18658148:170:58
status: NEW203 A, M961C/L1261C at the CL3/NBD2 interface; B, T966C/E543C at the CL3/NBD1 interface; C, V171C/L408C at the CL1/NBD1 interface; D, L171C/D1341C at the CL1/NBD2 interface.
X
ABCC7 p.Glu543Cys 18658148:203:52
status: NEW