ABCMdb

ABCC7 p.Lys716Arg

ClinVar:	c.2146A>T , p.Lys716* D , Pathogenic
Predicted by SNAP2:	A: D (53%), C: D (75%), D: D (75%), E: D (66%), F: D (80%), G: D (71%), H: D (53%), I: D (59%), L: D (59%), M: D (59%), N: D (53%), P: D (71%), Q: N (53%), R: N (53%), S: D (59%), T: N (57%), V: D (59%), W: D (85%), Y: D (80%),
Predicted by PROVEAN:	A: N, C: N, D: N, E: N, F: D, G: N, H: N, I: N, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: N,

[switch to compact view]
Comments [show]

None has been submitted yet.

Publications
[hide] Interference with ubiquitination in CFTR modifies ... Mol Cell Biol. 2014 Jul;34(14):2554-65. Lee S, Henderson MJ, Schiffhauer E, Despanie J, Henry K, Kang PW, Walker D, McClure ML, Wilson L, Sorscher EJ, Zeitlin PL
Interference with ubiquitination in CFTR modifies stability of core glycosylated and cell surface pools.
Mol Cell Biol. 2014 Jul;34(14):2554-65., [PMID:24777605]

Abstract [show]
It is recognized that both wild-type and mutant CFTR proteins undergo ubiquitination at multiple lysines in the proteins and in one or more subcellular locations. We hypothesized that ubiquitin is added to specific sites in wild-type CFTR to stabilize it and at other sites to signal for proteolysis. Mass spectrometric analysis of wild-type CFTR identified ubiquitinated lysines 68, 710, 716, 1041, and 1080. We demonstrate that the ubiquitinated K710, K716, and K1041 residues stabilize wild-type CFTR, protecting it from proteolysis. The polyubiquitin linkage is predominantly K63. N-tail mutants, K14R and K68R, lead to increased mature band CCFTR, which can be augmented by proteasomal (but not lysosomal) inhibition, allowing trafficking to the surface. The amount of CFTR in the K1041R mutant was drastically reduced and consisted of bands A/B, suggesting that the site in transmembrane 10 (TM10) was critical to further processing beyond the proteasome. The K1218R mutant increases total and cell surface CFTR, which is further accumulated by proteasomal and lysosomal inhibition. Thus, ubiquitination at residue 1218 may destabilize wild-type CFTR in both the endoplasmic reticulum (ER) and recycling pools. Small molecules targeting the region of residue 1218 to block ubiquitination or to preserving structure at residues 710 to 716 might be protein sparing for some forms of cystic fibrosis.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
73 We hypothe- TABLE 1 Primers for site-directed mutagenesis Mutation Directiona Sequence (5=-3=)b K14R F GGCCAGCGTTGTCTCCAGACTTTTTTTCAGCTGGACC R GGTCCAGCTGAAAAAAAGTCTGGAGACAACGCTGGCC K68R F GGCTTCAAAGAAAAATCCTAGACTCATTAATGCCCTTCGGCG R CGCCGAAGGGCATTAATGAGTCTAGGATTTTTCTTTGAAGCC K710R F CCAATCAACTCTATACGAAGATTTTCCATTGTGCAAAAG R CTTTTGCACAATGGAAAATCTTCGTATAGAGTTGATTGG K716R F GAAAATTTTCCATTGTGCAAAGGACTCCCTTACAAATGAATGG R CCATTCATTTGTAAGGGAGTCCTTTGCACAATGGAAAATTTTC K710/716R F CCAATCAACTCTATACGAAGATTTTCCATTGTGCAAAGGACTCCCTTACAAATGAATGG R CCATTCATTTGTAAGGGAGTCCTTTGCACAATGGAAAATCTTCGTATAGAGTTGATTGG K1041R F CCTCACAGCAATTCAGACAACTGGAATCTGAAG R CTTCAGATTCCAGTTGTCTGAGTTGCTGTGAGG K1080R F GAAACTCTGTTCCACAGAGCTCTGAATTTACATAC R GTATGTAAATTCAGAGCTCTGTGGAACAGAGTTTC K1218R F GATCTCACAGCAAGATACACAGAAGG R CCTTCTGTGTATCTTGCTGTGAGATC a F, forward; R, reverse. Login to comment
75 sized that ubiquitin might be required at these sites to stabilize the nascent protein, and the residues were mutated to arginine (K710R or K716R and the double mutant K710R K716R [K710/ 716R]). Login to comment
78 Interestingly, small perturbations in the predicted structure were seen with the K710R or K716R mutation alone but not when both residues were mutated in the same vector. Login to comment
81 At steady state and 37&#b0;C, the K710R and K716R mutations decrease the level of CFTR C band expression in whole-cell lysates, which suggests that the normally ubiquitinated K710 and K716 residues might be required to help process CFTR beyond the Golgi compartment (Fig. 2B). Login to comment
104 The observed reduction in expression of K710R, K716R, K710/ 716R, K1041R, and K1080R CFTRs might be the consequence of disordered conformational structure or folding/assembly. Login to comment
130 This immunoblot demonstrates increased levels of band C CFTR expression from the K14R, K68R, and K1218R cDNA vectors and decreased levels of band C CFTR expression in K710R, K716R, K710/716R, and K1080R vectors. Login to comment
139 We also expressed each of the R domain mutants (K710R, K716R, and K710/716R) during inhibition with MG132 and E64/ pepstatin A. Login to comment
140 Treatment with MG132 did not significantly increase A/B/C bands in the mutants, suggesting that K710R and K716R were not able to improve trafficking just because premature degradation was blocked and/or because lysosomal degradation was accelerated (Fig. 4B). Login to comment
166 (B) The results from expression of control vector, wt CFTR, K710R, K716R, and K710/716R with and without proteasomal or lysosomal inhibition are shown in representative blots, similar to the results show in panel A. MG132 increased wt CFTR band C as expected but did not affect band C of the mutants. Login to comment
177 K710R and K716R CFTRs reduce K63-linked polyubiquitination. Login to comment
183 Using an antibody specific for K63-linked polyubiquitin, we show that immunopurified CFTR has visibly less K63-linked polyubiquitination in the K710R and K716R mutants than the wild type (Fig. 5). Login to comment
191 The K710R, K716R, and K710/716R mutants showed faster degradation of the C band of CFTR than the wild type and K1218R. Login to comment
200 There were decreased levels of cell surface CFTR detection in the K68R, K710R, K716R, K710/ K716R, and K1041R mutant forms of CFTR, but the wild-type, K14R, K1080R, and K1218R mutants accumulated similar levels of visible cell surface CFTR. Login to comment
207 Again, there was a reduction in immunodetectable CFTR (K14R, K68R, K710R, K716R, K710/716R, and K1080R forms) in cell surface membranes compared to wild-type levels. Login to comment
213 These data demonstrate that by preventing ubiquitination at K710R and K716R, the CFTR mutants are then degraded in the lysosome. Login to comment
218 Control vector, wt CFTR, K14R, K68R, K710R, K716R, K710/716R, K1041R, K1080R, and K1218R were expressed in IB3-1 cells for 48 h. CFTR was immunoprecipitated (IP) with M3A7 as described in Materials and Methods and separated by SDS-PAGE. Login to comment
221 K63-linked ubiquitin on CFTR is reduced in the K68R, K710R, K716R, and K1218R mutants. Login to comment
275 Since ZO-1 interacts with PDZ domains, the reduced interactions in K14R, K68R, K710R, K716R, K710/716R, and K1041R and the absence of interactions with K1080R and K1218R raise the issue of alternative trafficking routes that are not dependent on the C-tail PDZ domain. Login to comment
278 Poly- or monoubiquitination in K14, K68, K710, K716, 1041, K1080, and K1218 sites allows CFTR to pass through its regular quality control process, producing adequate band C. K710R, K716R, K710/K716R, and K1080R mutants undergo some proteasome- and some lysosome-dependent degradation, whereas K1041R is primarily degraded by the proteasome. Login to comment
296 Interestingly, ZO-1 was highly abundant in complexes formed with wt CFTR; K14R, K68R, K710R, K716R, K710/716R, and K1041R mutants bound less ZO-1, whereas K1080R and K1218R mutant complexes had none. Login to comment