Western blot of rat brain homogenate showing specific immunolabeling of the ~59 kDa, ~65 kDa, ~68 kDa Tau isoforms phosphorylated at Ser416 in the first lane (-). Phosphospecificity is shown in the second lane (+) where immunolabeling is blocked by preadsorption with the phosphopeptide used as antigen, but not by the corresponding non-phosphopeptide (not shown).