Skip to main content
Log in

Burst Kinetics of Co-expressed Kir6.2/SUR1 Clones: Comparison of Recombinant with Native ATP-sensitive K+ Channel Behavior

  • Published:
The Journal of Membrane Biology Aims and scope Submit manuscript

Abstract.

Co-expression of clones encoding Kir6.2, a K+ inward rectifier, and SUR1, a sulfonylurea receptor, reconstitutes elementary features of ATP-sensitive K+ (KATP) channels. However, the precise kinetic properties of Kir6.2/SUR1 clones remain unknown. Herein, intraburst kinetics of Kir6.2/SUR1 channel activity, heterologously co-expressed in COS cells, displayed mean closed times from 0.7 ± 0.1 to 0.4 ± 0.03 msec, and from 0.4 ± 0.1 to 2.0 ± 0.2 msec, and mean open times from 1.9 ± 0.4 to 4.5 ± 0.8 msec, and from 12.1 ± 2.4 to 5.0 ± 0.2 msec between −100 and −20 mV, and +20 to +80 mV, respectively. Burst duration for Kir6.2/SUR1 activity was 17.9 ± 1.8 msec with 5.6 ± 1.5 closings per burst. Burst kinetics of the Kir6.2/SUR1 activity could be fitted by a four-state kinetic model defining transitions between one open and three closed states with forward and backward rate constants of 1905 ± 77 and 322 ± 27 sec−1 for intraburst, 61.8 ± 6.6 and 23.9 ± 5.8 sec−1 for interburst, 12.4 ± 6.0 and 13.6 ± 2.9 sec−1 for intercluster events, respectively. Intraburst kinetic properties of Kir6.2/SUR1 clones were essentially indistinguishable from pancreatic or cardiac KATP channel phenotypes, indicating that intraburst kinetics per se were insufficient to classify recombinant Kir6.2/SUR1 amongst native KATP channels. Yet, burst kinetic behavior of Kir6.2/SUR1 although similar to pancreatic, was different from that of cardiac KATP channels. Thus, expression of Kir6.2/SUR1 proteins away from the pancreatic micro-environment, confers the burst kinetic identity of pancreatic, but not cardiac KATP channels. This study reports the kinetic properties of Kir6.2/SUR1 clones which could serve in the further characterization of novel KATP channel clones.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Author information

Authors and Affiliations

Authors

Additional information

Received: 12 March 1997/Revised: 5 May 1997

Rights and permissions

Reprints and permissions

About this article

Cite this article

Alekseev, A., Kennedy, M., Navarro, B. et al. Burst Kinetics of Co-expressed Kir6.2/SUR1 Clones: Comparison of Recombinant with Native ATP-sensitive K+ Channel Behavior . J. Membrane Biol. 159 , 161 –168 (1997). https://doi.org/10.1007/s002329900279

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/s002329900279

Navigation