Stages and conformations of the Tau repeat domain during aggregation and its effect on neuronal toxicity.
Several neurodegenerative diseases are characterized by the aggregation and posttranslational modifications of Tau protein. Its "repeat domain" (TauRD) is mainly responsible for the aggregation properties, and oligomeric forms are thought to dominate the toxic effects of Tau. Here we investigated the conformational transitions of this domain during oligomerization and aggregation in different states of β-propensity and pseudo-phosphorylation, using several complementary imaging and spectroscopic methods. Although the repeat domain generally aggregates more readily than full-length Tau, its aggregation was greatly slowed down by phosphorylation or pseudo-phosphorylation at the KXGS motifs, concomitant with an extended phase of oligomerization. Analogous effects were observed with pro-aggregant variants of TauRD. Oligomers became most evident in the case of the pro-aggregant mutant TauRDΔK280, as monitored by atomic force microscopy, and the fluorescence lifetime of Alexa-labeled Tau (time-correlated single photon counting (TCSPC)), consistent with its pronounced toxicity in mouse models. In cell models or primary neurons, neither oligomers nor fibrils of TauRD or TauRDΔK280 had a toxic effect, as seen by assays with lactate dehydrogenase and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, respectively. However, oligomers of pro-aggregant TauRDΔK280 specifically caused a loss of spine density in differentiated neurons, indicating a locally restricted impairment of function.
From the German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, the Max Planck Institute for Neurological Research, Hamburg Outstation, c/o DESY, 22607 Hamburg, Germany, and.
Satish
S
Kumar
From the German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, the Center of Advanced European Studies and Research (CAESAR), 53175 Bonn, Germany.
Katharina
K
Tepper
From the German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, the Max Planck Institute for Neurological Research, Hamburg Outstation, c/o DESY, 22607 Hamburg, Germany, and.
Senthilvelrajan
S
Kaniyappan
From the German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, the Max Planck Institute for Neurological Research, Hamburg Outstation, c/o DESY, 22607 Hamburg, Germany, and the Center of Advanced European Studies and Research (CAESAR), 53175 Bonn, Germany.
Jacek
J
Biernat
the Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zürich, Basel, 4058 Basel, Switzerland.
Susanne
S
Wegmann
From the German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, the Max Planck Institute for Neurological Research, Hamburg Outstation, c/o DESY, 22607 Hamburg, Germany, and the Center of Advanced European Studies and Research (CAESAR), 53175 Bonn, Germany.
Eva-Maria
EM
Mandelkow
the Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zürich, Basel, 4058 Basel, Switzerland.
Daniel J
DJ
Müller
From the German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, the Max Planck Institute for Neurological Research, Hamburg Outstation, c/o DESY, 22607 Hamburg, Germany, and the Center of Advanced European Studies and Research (CAESAR), 53175 Bonn, Germany, Eckhard.Mandelkow@dzne.de.
Eckhard
E
Mandelkow
D000544:Alzheimer Disease / Q000209:etiology / Q000378:metabolism; D020816:Amino Acid Motifs; D000818:Animals; D002477:Cells; D002478:Cells, Cultured; D049229:Dendritic Spines / Q000378:metabolism / Q000473:pathology; D006801:Humans; D051379:Mice; D018625:Microscopy, Atomic Force; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism* / Q000473:pathology*; D010766:Phosphorylation; D011487:Protein Conformation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D020449:Repetitive Sequences, Amino Acid; D016875:tau Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
C054369:MAPT protein, human; D050505:Mutant Proteins; D016875:tau Proteins
Aggregation; Neuron; Oligomers; Phosphorylation; Synapse; Tau Protein (Tau); Time-correlated Single Photon Counting; Toxicity