Western blot of rat brainstem lysate showing specific immunolabeling of the ~55k TPH protein phosphorylated at Ser260 using TPH1 (phospho Ser260) antibody (GTX82573). The labeling is specifically blocked by the phosphopeptide (Phos-pep) used as antigen. The corresponding non-phosphopeptide (Nonphos-pep) did not block the immunolabeling.