Figure 3.

Isoforms mimicking the (de)phosphorylated state of S321 and S328 induce cell death, irrespective of cell-cell contact. Expression of (A) Cx37-S321D (green), (B) Cx37-S328D (blue), and (C) Cx37-S328A (red) induces cell death at low and high density. Insets highlight growth effects in cell cultures with few cell-cell contacts. dox -, no protein expression; dox +, induced Cx37 expression; Δ dox, cells grown to a higher cell density in the absence of dox for 12–14 days, after which dox was included in the media to induce expression, denoted by grey hash. n = 3 in triplicate for each isoform and dox treatment protocol. p < 0.05 for dox + versus dox − for all mutants (†), as well as WT (∗). For dox-switch experiments, ‡ indicates p < 0.05 for growth rate before versus after dox addition. All values are mean ± s.e.m (where error bars are not evident, they are smaller than the symbol size).