Fig. 1.

Sigma1 receptors (Sigma1R) co-expression has no effect on the voltage-dependent activation and E_rev of Kv1.3. A. Currents through Kv1.3 or Kv1.3 co-expressed with Sigma1R were elicited by 800 ms depolarizing voltage steps from −80 to +30mV in 10mV increments, applied from a holding potential of −100 mV (inset). IV plots were constructed from peak currents evoked by voltage steps. B. Tail currents elicited by voltage steps from −120 to −30 mV after 60 ms depolarizing prepulse to 0 mV, applied from a holding potential −100 mV. The potential at which no current is observed is the reversal potential (E_rev). C. Peak currents at respective voltages normalizing to the maximum current divided by the driving force yielded the gV plot that demonstrates the voltage dependence of channel activation. The smooth curve is the best fitting Boltzmann function. For Kv1.3 alone, n=7; for Kv1.3+Sigma1R, n=9. D. Lysates were prepared from mechanically isolated Xenopus oocytes membranes non-injected or injected with Kv1.3-HA alone, or with Sigma1R-FLAG cRNA. Approximately 3 µg protein was loaded in all lanes, resolved with SDS-PAGE, and replicate membranes were immunoblotted with anti-HA or anti-FLAG antibodies.