ABCMdb

ABCC7 p.Asp1341Cys

Predicted by SNAP2:	A: D (71%), C: D (75%), E: N (87%), F: D (85%), G: D (85%), H: D (80%), I: D (85%), K: D (91%), L: D (91%), M: D (85%), N: N (53%), P: D (85%), Q: D (71%), R: D (91%), S: D (75%), T: D (80%), V: D (85%), W: D (91%), Y: D (63%),
Predicted by PROVEAN:	A: D, C: D, E: N, F: D, G: D, H: N, I: D, K: N, L: D, M: D, N: N, P: D, Q: N, R: D, S: N, T: D, V: D, W: D, Y: D,

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Publications
[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). Login to comment
102 C, L172C/D1341C at the CL1/NBD2 interface and N268C/D1341C at the CL2/NBD2 interface at the X-loop of NBD2. Login to comment
127 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). Login to comment
173 On the other hand, the cross-linking between L172C of CL1 and D1341C of NBD2 rapidly and reversibly inhibited channel gating (Fig. 6D) very similar to what we had observed previously for the CL2/NBD2 interface (19). Login to comment
174 However, in the case of the completely reversible cessation of gating caused by L172C/D1341C cross-linking, the role of modification of each of these cysteines individually will have to be studied in detail because treatment with monofunctional MTSES also inhibited gating. Login to comment
203 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. Login to comment