title: Casein kinase II induced polymerization of soluble TDP-43 into filaments is inhibited by heat shock proteins.
abstract: BACKGROUND
  Trans-activation Response DNA-binding Protein-43 (TDP-43) lesions are observed in Amyotrophic Lateral Sclerosis (ALS), Frontotemporal Lobar Degeneration with ubiquitin inclusions (FTLD-TDP) and 25-50% of Alzheimer's Disease (AD) cases. These abnormal protein inclusions are composed of either amorphous TDP-43 aggregates or highly ordered filaments. The filamentous TDP-43 accumulations typically contain clean 10-12 nm filaments though wider 18-20 nm coated filaments may be observed. The TDP-43 present within these lesions is phosphorylated, truncated and ubiquitinated, and these modifications appear to be abnormal as they are linked to both a cellular heat shock response and microglial activation. The mechanisms associated with this abnormal TDP-43 accumulation are believed to result in a loss of TDP-43 function, perhaps due to the post-translational modifications or resulting from physical sequestration of the TDP-43. The formation of TDP-43 inclusions involves cellular translocation and conversion of TDP-43 into fibrillogenic forms, but the ability of these accumulations to sequester normal TDP-43 and propagate this behavior between neurons pathologically is mostly inferred. The lack of methodology to produce soluble full length TDP-43 and recapitulate this polymerization into filaments as observed in disease has limited our understanding of these pathogenic cascades.
  
  
  RESULTS
  The protocols described here generate soluble, full-length and untagged TDP-43 allowing for a direct assessment of the impact of various posttranslational modifications on TDP-43 function. We demonstrate that Casein Kinase II (CKII) promotes the polymerization of this soluble TDP-43 into 10 nm diameter filaments that resemble the most common TDP-43 structures observed in disease. Furthermore, these filaments are recognized as abnormal by Heat Shock Proteins (HSPs) which can inhibit TDP-43 polymerization or directly promote TDP-43 filament depolymerization.
  
  
  CONCLUSIONS
  These findings demonstrate CKII induces polymerization of soluble TDP-43 into filaments and Hsp90 promotes TDP-43 filament depolymerization. These findings provide rational for potential therapeutic intervention at these points in TDP-43 proteinopathies.
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Yari
authors.initials: Y
authors.lastname: Carlomagno
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Mary
authors.initials: M
authors.lastname: Davis
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Wen-Lang
authors.initials: WL
authors.lastname: Lin
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Casey
authors.initials: C
authors.lastname: Cook
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Judy
authors.initials: J
authors.lastname: Dunmore
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: William
authors.initials: W
authors.lastname: Tay
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Kyle
authors.initials: K
authors.lastname: Menkosky
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Xiangkun
authors.initials: X
authors.lastname: Cao
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Leonard
authors.initials: L
authors.lastname: Petrucelli
authors.affiliation: Department of Neuroscience, Maya Clinic, Jacksonville, Florida, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Deture
mesh_terms: D000818:Animals; D047390:Casein Kinase II / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D057174:Frontotemporal Lobar Degeneration / Q000378:metabolism / Q000473:pathology; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D002479:Inclusion Bodies / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D058105:Polymerization / Q000187:drug effects*; D066263:Protein Aggregation, Pathological / Q000378:metabolism; D015203:Reproducibility of Results; D012995:Solubility
chemical_list: D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D047390:Casein Kinase II