Role of the C-terminus of SUR in the differential regulation of β-cell and cardiac K_ATP channels by MgADP and metabolism.

ABSTRACT:

Key points

β-Cell K_ATP channels are partially open in the absence of metabolic substrates, whereas cardiac K_ATP channels are closed. Using cloned channels heterologously expressed in Xenopus oocytes we measured the effect of MgADP on the MgATP concentration-inhibition curve immediately after patch excision. MgADP caused a far more striking reduction in ATP inhibition of Kir6.2/SUR1 channels than Kir6.2/SUR2A channels; this effect declined rapidly after patch excision. Exchanging the final 42 amino acids of SUR was sufficient to switch the Mg-nucleotide regulation of Kir6.2/SUR1 and Kir6.2/SUR2A channels, and partially switch their sensitivity to metabolic inhibition. Deletion of the C-terminal 42 residues of SUR abolished MgADP activation of both Kir6.2/SUR1 a

SUBMITTER: Vedovato N 

PROVIDER: S-EPMC6292810 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature