Tar DNA Binding Protein-43 (TDP-43) Associates with Stress Granules: Analysis of Cultured Cells and Pathological Brain Tissue

• Published in: PloS one Vol. 5; no. 10; p. e13250
• Main Authors: Liu-Yesucevitz, Liqun, Bilgutay, Aylin, Zhang, Yong-Jie, Vanderwyde, Tara, Citro, Allison, Mehta, Tapan, Zaarur, Nava, McKee, Ann, Bowser, Robert, Sherman, Michael, Petrucelli, Leonard, Wolozin, Benjamin
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 11.10.2010; Public Library of Science (PLoS)
• Subjects: Aberration; Accumulation; Amyotrophic lateral sclerosis; Analysis; Binding; Binding proteins; Biochemistry/Cell Signaling and Trafficking Structures; Blotting, Western; Brain; Brain - cytology; Brain - metabolism; Brain - pathology; Cell culture; Cells, Cultured; Central nervous system; Cytoplasm; Cytoplasm - metabolism; Degeneration; Deoxyribonucleic acid; Disease; DNA; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drosophila; Fluorescence; Frontotemporal dementia; Frontotemporal Lobar Degeneration - metabolism; Frontotemporal Lobar Degeneration - pathology; Gene Knockdown Techniques; Genetic research; Granular materials; Granule cells; Health risk assessment; Humans; Inclusion bodies; Inclusions; Insects; Localization; Medicine; Metabolism; Molecular Biology/RNA-Protein Interactions; Molecular Biology/Translational Regulation; mRNA; Mutation; Neuroblastoma; Neurodegeneration; Neurological Disorders/Movement Disorders; Neurosciences; Pathology; Pharmacology; Physiological aspects; Protein binding; Protein interaction; Protein turnover; Protein-protein interactions; Proteins; Ribonucleic acid; RNA; Rodents; Signal transduction; Signaling; Transgenic animals; Transient ischemic attack; Translation (Genetics); Florida; United States > US; Massachusetts
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0013250

Tar DNA Binding Protein-43 (TDP-43) is a principle component of inclusions in many cases of frontotemporal lobar degeneration (FTLD-U) and amyotrophic lateral sclerosis (ALS). TDP-43 resides predominantly in the nucleus, but in affected areas of ALS and FTLD-U central nervous system, TDP-43 is aberrantly processed and forms cytoplasmic inclusions. The mechanisms governing TDP-43 inclusion formation are poorly understood. Increasing evidence indicates that TDP-43 regulates mRNA metabolism by interacting with mRNA binding proteins that are known to associate with RNA granules. Here we show that TDP-43 can be induced to form inclusions in cell culture and that most TDP-43 inclusions co-localize with SGs. SGs are cytoplasmic RNA granules that consist of mixed protein-RNA complexes. Under stressful conditions SGs are generated by the reversible aggregation of prion-like proteins, such as TIA-1, to regulate mRNA metabolism and protein translation. We also show that disease-linked mutations in TDP-43 increased TDP-43 inclusion formation in response to stressful stimuli. Biochemical studies demonstrated that the increased TDP-43 inclusion formation is associated with accumulation of TDP-43 detergent insoluble complexes. TDP-43 associates with SG by interacting with SG proteins, such as TIA-1, via direct protein-protein interactions, as well as RNA-dependent interactions. The signaling pathway that regulates SGs formation also modulates TDP-43 inclusion formation. We observed that inclusion formation mediated by WT or mutant TDP-43 can be suppressed by treatment with translational inhibitors that suppress or reverse SG formation. Finally, using Sudan black to quench endogenous autofluorescence, we also demonstrate that TDP-43 positive-inclusions in pathological CNS tissue co-localize with multiple protein markers of stress granules, including TIA-1 and eIF3. These data provide support for accumulating evidence that TDP-43 participates in the SG pathway.