ABCMdb

PMID: 9831713

Proks P, Gribble FM, Adhikari R, Tucker SJ, Ashcroft FM
Involvement of the N-terminus of Kir6.2 in the inhibition of the KATP channel by ATP.
J Physiol. 1999 Jan 1;514 ( Pt 1):19-25., [PubMed]

Sentences

No. Mutations Sentence Comment

18 ABCC8 p.Ile49Gly ABCC8 p.Ile49Gly Mutation of the isoleucine residue at position 49 to glycine (I49G) reduced the channel ATP sensitivity, while the mutation of the glutamate residue at position 51 to glycine (E51G) did not. Login to comment 103 ABCC8 p.Ile49Gly ABCC8 p.Ile49Gly However when the isoleucine at position 49 was changed to glycine, ATP produced significantly less inhibition (I49G; Figs 3 and 5). Login to comment 106 ABCC8 p.Ile49Gly Single-channel currents for wild-type and mutant Kir6.2ÄC26 channels Single-channel currents recorded at -60 mV from an inside-out patch excised from an oocyte injected with mRNA encoding wtKir6.2ÄC26 or Kir6.2ÄC26-I49G, in the absence and presence of ATP as indicated. Login to comment 109 ABCC8 p.Ile49Gly Comparison of wild-type and mutant Kir6.2ÄC26 single-channel kinetics ------------------------------------------------------------ Clone Pï ôï ôC1 ôC2 %Cµ Burst duration Openings (n = 3) (ms) (ms) (ms) (ms) per burst ------------------------------------------------------------ Kir6.2ÄC26 0·11 ± 0·03 0·79 ± 0·06 0·31 ± 0·03 12·6 ± 2·9 41 ± 8 2·4 ± 0·6 2·4 ± 0·3 Kir6.2ÄC26-R50G 0·14 ± 0·07 0·99 ± 0·09 0·32 ± 0·01 9·1 ± 3·1 36 ± 3 2·6 ± 0·5 2·1 ± 0·4 Kir6.2ÄC26-R50A 0·09 ± 0·02 0·71 ± 0·04 0·29 ± 0·01 17·1 ± 4·7 44 ± 7 2·8 ± 0·6 2·6 ± 0·4 Kir6.2ÄC26-R50SÏE179Q 0·08 ± 0·02 0·75 ± 0·0 0·28 ± 0·01 9·4 ± 1·9 50 ± 2 2·7 ± 0·3 2·8 ± 0·3 Kir6.2ÄC26-I49G 0·13 ± 0·04 0·85 ± 0·07 0·29 ± 0·03 7·3 ± 1·8 32 ± 4 2·9 ± 0·2 2·7 ± 0·2 ------------------------------------------------------------ Kinetic parameters were measured at -60 mV, as described in Trapp et al. (1978). Login to comment 115 ABCC8 p.Ile49Gly The reduced ATP sensitivity of the I49G mutant channel was not associated with a change in the single-channel kinetics (Fig. 5 and Table 2), suggesting that this mutation impairs either ATP binding or the mechanism by which binding is linked to channel closure. Login to comment 139 ABCC8 p.Pro69Arg Several other mutations in the N_terminus, including N41A, K47N, Q52A and P69R were without marked effect on the ATP P. Proks, F. M. Gribble, R. Adhikari, S. J. Tucker and F. M. Ashcroft J. Physiol. 514.124 Figure 6. Login to comment