ABCMdb

PMID: 21617188

Mannikko R, Flanagan SE, Sim X, Segal D, Hussain K, Ellard S, Hattersley AT, Ashcroft FM
Mutations of the same conserved glutamate residue in NBD2 of the sulfonylurea receptor 1 subunit of the KATP channel can result in either hyperinsulinism or neonatal diabetes.
Diabetes. 2011 Jun;60(6):1813-22., [PubMed]

Sentences

No. Mutations Sentence Comment

0 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly Mutations of the Same Conserved Glutamate Residue in NBD2 of the Sulfonylurea Receptor 1 Subunit of the KATP Channel Can Result in Either Hyperinsulinism or Neonatal Diabetes Roope Männikkö,1 Sarah E. Flanagan,2 Xiuli Sim,1 David Segal,3 Khalid Hussain,4 Sian Ellard,2 Andrew T. Hattersley,2 and Frances M. Ashcroft1 OBJECTIVE-Two novel mutations (E1506D, E1506G) in the nucleotide-binding domain 2 (NBD2) of the ATP-sensitive K+ channel (KATP channel) sulfonylurea receptor 1 (SUR1) subunit were detected heterozygously in patients with neonatal diabetes. Login to comment 1 ABCC8 p.Glu1506Lys A mutation at the same residue (E1506K) was previously shown to cause congenital hyperinsulinemia. Login to comment 6 ABCC8 p.Glu1506Lys Conversely, no E1506K currents were recorded at rest or after metabolic inhibition, as expected for a mutation causing hyperinsulinemia. Login to comment 9 ABCC8 p.Glu1506Lys Importantly, using wild-type Kir6.2, a 30-s preconditioning exposure to physiological MgATP concentrations (.300 mmol/L) caused a marked reduction in the ATP sensitivity of neonatal diabetic channels, a small decrease in that of wild-type channels, and no change for E1506K channels. Login to comment 49 ABCC8 p.Glu1506Lys Furthermore, the mutation of E1506 to lysine (E1506K) results in reduced channel activation by MgADP and is associated with hyperinsulinism (26,27). Login to comment 50 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly Furthermore, the mutation of E1506 to lysine (E1506K) results in reduced channel activation by MgADP and is associated with hyperinsulinism (26,27). Login to comment 51 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly This article reports our investigation of how the mutation of E1506 to aspartate (E1506D) or glycine (E1506G) results in the opposite clinical condition of neonatal diabetes. Login to comment 78 ABCC1 p.Glu1507Asp We identified novel heterozygous ABCC8 mutations, E1507D (c.4521G. Login to comment 79 ABCC1 p.Glu1507Asp ABCC1 p.Glu1507Gly We identified novel heterozygous ABCC8 mutations, E1507D (c.4521G. Login to comment 80 ABCC1 p.Glu1507Gly T) and E1507G (c.4520A.G), in two male probands. Login to comment 81 ABCC1 p.Glu1507Asp Proband 1 with the E1507D mutation weighed 2.9 kg at birth (42 weeks` gestation) and was diagnosed as insulin-dependent at 10 weeks. Login to comment 82 ABCC1 p.Glu1507Asp Proband 1 with the E1507D mutation weighed 2.9 kg at birth (42 weeks` gestation) and was diagnosed as insulin-dependent at 10 weeks. Login to comment 85 ABCC1 p.Glu1507Gly After an E1507G mutation was identified, the patient was successfully transferred from insulin to glibenclamide at the age of 6 months. Login to comment 86 ABCC1 p.Glu1507Gly After an E1507G mutation was identified, the patient was successfully transferred from insulin to glibenclamide at the age of 6 months. Login to comment 88 ABCC1 p.Glu1507Asp ABCC1 p.Glu1507Gly A family history of diabetes had not been reported for either proband, and testing of parental samples demonstrated that the E1507D and E1507G mutations had each arisen de novo in the proband. Login to comment 89 ABCC1 p.Glu1507Asp ABCC1 p.Glu1507Gly A family history of diabetes had not been reported for either proband, and testing of parental samples demonstrated that the E1507D and E1507G mutations had each arisen de novo in the proband. Login to comment 95 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly A small but significant increase in resting current was observed for both homomeric Kir6.2/SUR1-E1506D (homE1506D) and Kir6.2/SUR1-E1506G (homE1506G) channels (Fig. 1). Login to comment 96 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly A small but significant increase in resting current was observed for both homomeric Kir6.2/SUR1-E1506D (homE1506D) and Kir6.2/SUR1-E1506G (homE1506G) channels (Fig. 1). Login to comment 97 ABCC8 p.Glu1506Lys As previously reported (27), Kir6.2/SUR1-E1506K (homE1506K) currents were minimal in both the absence and presence of azide but were slightly increased by diazoxide. Login to comment 98 ABCC8 p.Glu1506Lys As previously reported (27), Kir6.2/SUR1-E1506K (homE1506K) currents were minimal in both the absence and presence of azide but were slightly increased by diazoxide. Login to comment 99 ABCC8 p.Glu1506Asp The resting currents of heterozygous (het) E1506D and hetE1506G channels were significantly greater than wild-type channels, which may explain why these mutations cause neonatal diabetes. Login to comment 100 ABCC8 p.Glu1506Asp The resting currents of heterozygous (het) E1506D and hetE1506G channels were significantly greater than wild-type channels, which may explain why these mutations cause neonatal diabetes. Login to comment 104 ABCC8 p.Glu1506Lys Tolbutamide (500 mmol/L) blocked hetE1506D currents by 95 6 1% (n = 8), hetE1506G currents by 95 6 1% (n = 6), and E1506K currents by 91 6 2% (n = 6) compared with 96 6 1% (n = 7) for wild-type channels. Login to comment 105 ABCC8 p.Glu1506Lys Tolbutamide (500 mmol/L) blocked hetE1506D currents by 95 6 1% (n = 8), hetE1506G currents by 95 6 1% (n = 6), and E1506K currents by 91 6 2% (n = 6) compared with 96 6 1% (n = 7) for wild-type channels. Login to comment 110 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly This suggests that the neonatal diabetes mutations have little (E1506D) or no (E1506G) effect on expression levels of the KATP channel in the heterozygous state. Login to comment 111 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly This suggests that the neonatal diabetes mutations have little (E1506D) or no (E1506G) effect on expression levels of the KATP channel in the heterozygous state. Login to comment 114 ABCC8 p.Glu1506Asp A-C: Representative whole-cell current amplitudes evoked by repeated voltage steps from 210 to 230 mV for wild-type (A, WT), and homomeric (B, homE1506D) or heterozygous (C, hetE1506D) Kir6.2/SUR1-E1506D channels. Login to comment 115 ABCC8 p.Glu1506Asp A-C: Representative whole-cell current amplitudes evoked by repeated voltage steps from 210 to 230 mV for wild-type (A, WT), and homomeric (B, homE1506D) or heterozygous (C, hetE1506D) Kir6.2/SUR1-E1506D channels. Login to comment 135 ABCC8 p.Glu1506Asp B: Kir6.2/SUR1-E1506D (n = 11), IC50 = 20.1, h = 1.05. Login to comment 136 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly B: Kir6.2/SUR1-E1506D (n = 11), IC50 = 20.1, h = 1.05. Login to comment 137 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Gly C: Kir6.2/SUR1-E1506G (n = 10), IC50 = 18.8, h = 0.93. Login to comment 138 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp D: Kir6.2/SUR1-E1506K (n = 11), IC50 = 11.0, h = 1.14. Login to comment 139 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly E: Kir6.2/SUR1-E1506D (n = 7), IC50 = 8.2, h = 1.00. Login to comment 140 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Gly F: Kir6.2/SUR1-E1506G (n = 7), IC50 = 6.9, h = 0.86. Login to comment 141 ABCC8 p.Glu1506Lys G: SUR1-E1506K (n = 7), IC50 = 6.4, h = 1.00. stimulation at SUR1 because ATP does not interact with SUR1 in the absence of Mg2+ (34). Login to comment 178 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly No increase in current was observed for the Kir6.2-G334D/SUR1-E1506D (G334D/E1506D) or Kir6.2-G334D/SUR1-E1506G (G334D/ E1506G) channels; in contrast, the Kir6.2-G334D/SUR1-E1506K (G334D/E1506K) currents increased 1.5-fold on excision. Login to comment 179 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly No increase in current was observed for the Kir6.2-G334D/SUR1-E1506D (G334D/E1506D) or Kir6.2-G334D/SUR1-E1506G (G334D/ E1506G) channels; in contrast, the Kir6.2-G334D/SUR1-E1506K (G334D/E1506K) currents increased 1.5-fold on excision. Login to comment 180 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly This suggests that the G334D/E1506 and G334D/ E1506K channels were partially blocked under resting conditions in the oocyte, whereas the G334D/E1506D and G334D/E1506G channels were fully open. Login to comment 181 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly ABCC8 p.Glu1506Gly Larger amplitudes were found for the G334D/E1506 (8.5 6 1.9 nA, n = 16) and G334D/E1506K (14 6 1.9 nA, n = 9) currents than for the G334D/E1506D (1.0 6 0.2 nA, n = 11) or G334D/ E1506G (0.8 6 0.2 nA, n = 13) currents, again suggesting that the E1506D and E1506G mutations may impair surface expression in the homomeric state. Login to comment 192 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp The error bars show the SEM. E: Representative current traces for WT and Kir6.2/SUR1-E1506D (E1506D) channels. Login to comment 193 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp The error bars show the SEM. E: Representative current traces for WT and Kir6.2/SUR1-E1506D (E1506D) channels. Login to comment 194 ABCC8 p.Glu1506Asp The WT trace is interrupted to align the time point of ATP removal with that of the E1506D trace. Login to comment 195 ABCC8 p.Glu1506Asp The WT trace is interrupted to align the time point of ATP removal with that of the E1506D trace. Login to comment 203 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly The off-rate of MgADP was not significantly different for the G334D/E1506K channels but was slower for the G334D/E1506D and G334D/E1506G channels, with a toff of 10 and 11 s, respectively. Login to comment 204 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly The off-rate of MgADP was not significantly different for the G334D/E1506K channels but was slower for the G334D/E1506D and G334D/E1506G channels, with a toff of 10 and 11 s, respectively. Login to comment 205 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly The off-rate of MgATP was significantly less for all three mutant channels, with a toff of 8.5 s for G334D/E1506K, 16 s for G334D/E1506G, and 67 s for G334D/E1506D. Login to comment 209 ABCC8 p.Glu1506Lys Such ATP preconditioning reduced the ATP sensitivity of the two neonatal diabetic mutant channels but had little or no effect on wild-type or E1506K channels, respectively (Table 1). Login to comment 210 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly Such ATP preconditioning reduced the ATP sensitivity of the two neonatal diabetic mutant channels but had little or no effect on wild-type or E1506K channels, respectively (Table 1). Login to comment 211 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly As a consequence, the IC50 for the ATP block of the homomeric and heterozygous E1506D and E1506G channels was significantly greater than wild-type, whereas that of hetE1506K was no different, and that of homE1506K was actually slightly smaller (Fig. 6, Table 1). Login to comment 212 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly Preconditioning pulses of .300 mmol/L MgATP markedly reduced the ability of 100 mmol/L MgATP to block E1506D and E1506G channels but had only a small effect on wild-type channels and no effect on the homE1506K channels. Login to comment 213 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly Preconditioning pulses of .300 mmol/L MgATP markedly reduced the ability of 100 mmol/L MgATP to block E1506D and E1506G channels but had only a small effect on wild-type channels and no effect on the homE1506K channels. Login to comment 237 ABCC8 p.Glu1506Lys In contrast, this effect was very small for wild-type channels and absent for E1506K channels. Login to comment 238 ABCC8 p.Glu1506Lys In contrast, this effect was very small for wild-type channels and absent for E1506K channels. Login to comment 251 ABCC8 p.Glu1506Asp Mutation of the equivalent residue in MRP1 to aspartate does not alter MgADP binding (32), which suggests that SUR1-E1506D might bind MgADP but that binding no longer leads to channel activation. Login to comment 252 ABCC8 p.Glu1506Asp Mutation of the equivalent residue in MRP1 to aspartate does not alter MgADP binding (32), which suggests that SUR1-E1506D might bind MgADP but that binding no longer leads to channel activation. Login to comment 263 ABCC8 p.Glu1506Asp The slower off-rate of MgATP seen with the neonatal diabetes mutations (especially E1506D) may indicate that the channel becomes trapped in a particular state of the reaction cycle that is associated with increased channel activity; for example, the MgATP-bound or MgADP + Pi state. Login to comment 264 ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp The slower off-rate of MgATP seen with the neonatal diabetes mutations (especially E1506D) may indicate that the channel becomes trapped in a particular state of the reaction cycle that is associated with increased channel activity; for example, the MgATP-bound or MgADP + Pi state. Login to comment 265 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly The off-rate of MgADP was much faster than that of MgATP for the E1506D channels, and MgADP had little stimulatory effect, which supports arguments that it cannot be the MgADP-bound state. Login to comment 266 ABCC8 p.Glu1506Lys ABCC8 p.Glu1506Asp ABCC8 p.Glu1506Gly The most striking difference between the E1506K and E1506G/E1506D channels is that shown in Figs. 6 and 7: pre-exposure to millimolar concentrations of MgATP desensitizes the channel to subsequent inhibition by a lower ATP concentration. Login to comment