Immunofluorescent staining of LA25 cells for total Cx43 (Cx43IF1) in the absence (A) or presence of a proteasomal inhibitor (B) and the resulting quantification of junction size (C) comparing control to the proteasomal inhibitor ALLN (red bars indicate the percent increase elicited by proteasome inhibition) and cells incubated at 40 °C (src inactive). In (D,E), cells were stained for total Cx43 (green, Cx43IF1) and pY247 (D, red) or pY265 (E, red), resulting overlay is yellow, and the ratios are indicated in (F). G shows a higher magnification view of a large gap junction showing old, new, and pY247 subdomains. A, B, D, F Mag bars are 20 µm, G is 1 µm. * and *** indicate p < 0.05 and p < 0.001, respectively.