Figure 3.

Ubiquitin colocalizes with tau, the ER, or other proteins in Tg brains. A–G, Quadruple immunofluorescent stain of tau (A,C,E,G; red), ubiquitin (B,C,F,G; green), calnexin (D–G; cyan), and neurons (G; blue) in the hippocampus of 9-month-old Tg mice (low-magnification scale bar, 100 μm). Insets show higher-magnification images (inset scale bar, 10 μm). G, Inset of the merged image shows tau-ubiquitin colocalization (white arrowhead), non-colocalizing ubiquitin (yellow arrowhead), and calnexin-ubiquitin colocalization (orange arrowhead). H, Graphical representation of the amount of colocalization, where 24% and 17% of ubiquitin (top green bar) colocalizes with tau or calnexin, respectively (Pearson > 0.5); however, tau and calnexin do not colocalize (Pearson < 0.5). Approximately 59% of the ubiquitin signal did not colocalize with either tau or calnexin. Red and cyan bars show that 60% of tau and 42% of calnexin are ubiquitinated, respectively; the remainder of the signal did not colocalize with ubiquitin.