ABCC7 p.Asp835Ala
| Predicted by SNAP2: | A: N (82%), C: N (57%), E: N (87%), F: D (59%), G: N (72%), H: N (57%), I: D (53%), K: N (66%), L: N (61%), M: D (59%), N: N (78%), P: N (57%), Q: N (82%), R: N (66%), S: N (82%), T: N (82%), V: N (72%), W: N (53%), Y: D (53%), |
| Predicted by PROVEAN: | A: D, C: D, E: N, F: D, G: D, H: D, 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, |
[switch to compact view]
Comments [show]
None has been submitted yet.
[hide] State-dependent regulation of cystic fibrosis tran... J Biol Chem. 2010 Dec 24;285(52):40438-47. Epub 2010 Oct 15. Wang G
State-dependent regulation of cystic fibrosis transmembrane conductance regulator (CFTR) gating by a high affinity Fe3+ bridge between the regulatory domain and cytoplasmic loop 3.
J Biol Chem. 2010 Dec 24;285(52):40438-47. Epub 2010 Oct 15., 2010-12-24 [PMID:20952391]
Abstract [show]
The unique regulatory (R) domain differentiates the human CFTR channel from other ATP-binding cassette transporters and exerts multiple effects on channel function. However, the underlying mechanisms are unclear. Here, an intracellular high affinity (2.3 x 10(-19) M) Fe(3+) bridge is reported as a novel approach to regulating channel gating. It inhibited CFTR activity by primarily reducing an open probability and an opening rate, and inhibition was reversed by EDTA and phenanthroline. His-950, His-954, Cys-832, His-775, and Asp-836 were found essential for inhibition and phosphorylated Ser-768 may enhance Fe(3+) binding. More importantly, inhibition by Fe(3+) was state-dependent. Sensitivity to Fe(3+) was reduced when the channel was locked in an open state by AMP-PNP. Similarly, a K978C mutation from cytoplasmic loop 3 (CL3), which promotes ATP-independent channel opening, greatly weakened inhibition by Fe(3+) no matter whether NBD2 was present or not. Therefore, although ATP binding-induced dimerization of NBD1-NBD2 is required for channel gating, regulation of CFTR activity by Fe(3+) may involve an interaction between the R domain and CL3. These findings may support proximity of the R domain to the cytoplasmic loops. They also suggest that Fe(3+) homeostasis may play a critical role in regulating pathophysiological CFTR activity because dysregulation of this protein causes cystic fibrosis, secretary diarrhea, and infertility.
Comments [show]
None has been submitted yet.
No. Sentence Comment
132 Fig. 4, B and E, indicate that only D836A dramatically prevented inhibition by Fe3ϩ , whereas E822A, E826A, D828A, E831A, and D835A did not.
X
ABCC7 p.Asp835Ala 20952391:132:132
status: NEW[hide] Regulation of Activation and Processing of the Cys... J Biol Chem. 2012 Oct 11. Wang G, Duan DD
Regulation of Activation and Processing of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) by a Complex Electrostatic Interaction between the Regulatory Domain and Cytoplasmic Loop 3.
J Biol Chem. 2012 Oct 11., [PMID:23060444]
Abstract [show]
NEG2, a short C-terminal segment (817-838) of the unique regulatory (R) domain of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, has been reported to regulate CFTR gating in response to cAMP-dependent R domain phosphorylation. The underlying mechanism, however, is unclear. Here, K946 of cytoplasmic loop 3 (CL3) is proposed as counter-ion of D835, D836 or E838 of NEG2 to prevent channel activation by PKA. R764 or R766 of the S768 phosphorylation site of the R domain is proposed to promote channel activation possibly by weakening the putative CL3-NEG2 electrostatic attraction. First, not only D835A, D836A and E838A but also K946A reduced the PKA dependent CFTR activation. Second, both K946D and D835R/D836R/E838R mutants were activated by ATP and curcumin to a different extent. Third, R764A and R766A mutants enhanced the PKA-dependent activation. On the other hand, it is very exciting that D835R/D836R/E838R and K946D/H950D and H950R exhibited normal channel processing and activity while D835R/D836R/E838R/K946D/H950D was misprocessed and silent in response to forskolin. Further, D836R and E838R played a critical role in the asymmetric electrostatic regulation of CFTR processing and S768 phosphorylation may not be involved. Thus, a complex interfacial interaction among CL3, NEG2 and the S768 phosphorylation site may be responsible for the asymmetric electrostatic regulation of CFTR activation and processing.
Comments [show]
None has been submitted yet.
No. Sentence Comment
11 First, not only D835A, D836A and E838A but also K946A reduced the PKA dependent CFTR activation.
X
ABCC7 p.Asp835Ala 23060444:11:16
status: NEW60 Similar observations with D835A and E838A were summarized in Fig. 2D. The K1/2 for PKA activation reduced from 10 units/ml to 5 units/ml once K946 from the CL3, and D835, D836 and E838 from NEG2 were mutated to alanines (Fig.2D).
X
ABCC7 p.Asp835Ala 23060444:60:26
status: NEW138 First, the PKA sensitivity of channel activation was significantly enhanced for K946A, D835A, D836A and E838A mutants (Fig.2).
X
ABCC7 p.Asp835Ala 23060444:138:87
status: NEW9 First, not only D835A, D836A, and E838A but also K946A reduced the PKA-dependent CFTR activation.
X
ABCC7 p.Asp835Ala 23060444:9:16
status: NEW63 Similar observations with D835A and E838A are summarized in Fig. 2D.
X
ABCC7 p.Asp835Ala 23060444:63:26
status: NEW167 First, the PKA sensitivity of channel activation was significantly enhanced for K946A, D835A, D836A, and E838A mutants (Fig. 2).
X
ABCC7 p.Asp835Ala 23060444:167:87
status: NEW