Fig. 2.

The Unx1 channel activity is increased by low extracellular concentration of divalent cations, and Ca²⁺ permeates the channels. (A) Time-course of DAPI uptake was evaluated in parental and Cx45 KO HeLa cells transfected with Unx1. The absence of extracellular Ca²⁺ and Mg²⁺ (DCFS) increased DAPI uptake, which was blocked by 200 µM lanthanum (La³⁺) or CBX. (B) Ca²⁺ signal (ratio of fluorescence emission at 340 and 380 nm) was evaluated in HeLa Unx1-EGFP cells loaded with Fura-2 and exposed to an extracellular solution without Mg²⁺, pH 8.5, and containing 1 mM orthovanadate (C and D). Data are presented as mean ± SEM; ^***P < 0.001 vs. basal. ^##P < 0.01, ^###P < 0.001 vs. DCFS (n = 3 to 8).