PANNEXIN 1 EXPRESSION IN XENOPUS LAEVIS OOCYTES

ADRIANA LOSAVIO; PABLO SCHWARZBAUM; JUAN GUARRACINO; KARINA ALLEVA; LUCIANO GALIZIA

CABA

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Six subunits of Pannexin 1 (Panx1) form a plasma membrane channel termed pannexon. The pannexon can function as a small-conductance chloride selective channel, activated by an in- crease of membrane potential (Vm). Alternatively, a non selective high- conductance mode was reported, where the channel can be activated by increases in extracellular potassium concentration (K+) e and permeate molecules less than 1.5 kD. In addition to K+e and Vm, hypotonicity was suggested -but not thoroughly proven- to activate Panx1 activity. In this context we used Xenopus oocytes as an expression system to express Panx1, and characterize the modulation of Panx1 cur- rents by K+e and hypotonicity. Expression of Panx1 was assessed by two-electrode voltage clamp technique. We employed a voltage step protocol to evalu- ate the small conductance mode or a continuous pulse protocol to observe the high conductance mode. By applying a voltage step protocol in Panx1 injected oocytes we observed voltage sensitive outward currents that were absent in water injected oocytes (Ipanx1 at 60 mV = 0.60 ± 0.12 μA, n=10 vs water at 60 mV 0.12 ± 0.01μA, n=7, p