Expression of functionally active ATP-sensitive K-channels in insect cells using baculovirus

Area of Science:

• Molecular Biology
• Cell Physiology
• Biophysics

Background:

• ATP-sensitive potassium channels (K(ATP) channels) are crucial for cellular energy homeostasis.
• Previous expression systems for K(ATP) channels have limitations in yield and functionality.

Purpose of the Study:

• To establish a robust system for expressing active K(ATP) channels in Spodoptera frugiperda (Sf9) insect cells.
• To characterize the functional properties of K(ATP) channels expressed in Sf9 cells.

Main Methods:

• Utilized a baculovirus vector for gene expression in Sf9 cells.
• Co-expressed SUR1 and Kir6.2 subunits, with engineered N- and/or C-terminal tags for detection.
• Employed Western blotting for protein detection and electrophysiology for channel activity assessment.

Main Results:

• Achieved high yields of active K(ATP) channels in Sf9 cells.
• Demonstrated ATP, glibenclamide, and diazoxide sensitivity of expressed channels.
• Observed ATP-sensitive but sulphonylurea-insensitive activity from a truncated Kir6.2 subunit (Kir6.2 deltaC26).
• Found that full-length Kir6.2 alone produced active channels in Sf9 cells, unlike in other systems.
• Identified a fusion protein of SUR1 and Kir6.2 deltaC26 as yielding the highest channel activity.

Conclusions:

• Sf9 insect cells provide an effective platform for high-yield expression of functional K(ATP) channels.
• The insect cell expression system allows for detailed functional analysis of K(ATP) channel subunits and their interactions.
• This system offers a valuable tool for future research into K(ATP) channel function and pharmacology.