Figure 13.

Vj sensitivity of homotypic Cx32 (32–32) or heterotypic tandem–Cx32 (tandem-32) channels monitored in Xenopus oocyte pairs. With the application of Vj in steps (20–120 mV), 32–32 channels display a typical Vj sensitivity, as Ij decays exponentially for Vj > ±20–40 mV (A,B). In contrast, tandem–32 channels display a unique Ij–Vj behavior: with a negative mutant side, initial and final Ij progressively decrease to very low values, while with a positive mutant side, Ij progressively increases to high values. The large asymmetry in the relationship between Vj and normalized Gj (G_jss/G_jmax; (A) is eliminated by the inhibition of CaM expression (B). From Reference [105].