Clinical Neuroscience And NeuropathologyParadoxical phosphorylation of the serine 199 on tau proteins from young individualsMaurage, Claude-Alain1,2; Sergeant, Nicolas1; Ruchoux, Marie-Magdeleine2; Hauw, Jean-Jacques3; Delacourte, André1, CAAuthor Information 1INSERM U422, 1 Place de Verdun, 59045 Lille; 2Department of Neuropathology, CHRU, 59037 Lille; 3Department of Neuropathology and INSERM U360, CHU Pitié-Salpétrière, Paris, France CACorresponding Author Received 17 July 2001; accepted 6 August 2001 NeuroReport: October 29th, 2001 - Volume 12 - Issue 15 - p 3177-3181 Buy Abstract The microtubule-associated tau proteins are abnormally aggregated in many tauopathies. Phosphorylation modulates the functions of tau. The serine 199 residue of tau is abnormally phosphorylated at early and late stages of Alzheimer's disease. The presence of the phosphorylated Ser199 was investigated in autopsy-derived and biopsy-derived brain tissue samples from non-demented individuals. A paradoxical expression was found in the hippocampus of the youngest ones, in granule cells of the dentate gyrus and in pyramidal cells of the Ammon's horn, which are particularly prone to neurodegeneration in several tauopathies. The rate of positive cells decreased with age. These data emphasize the importance of the phosphorylation of the Ser199 residue of tau in ageing and susceptibility to neurodegeneration. © 2001 Lippincott Williams & Wilkins, Inc.