title: Quantitative phosphoproteomics of Alzheimer's disease reveals cross-talk between kinases and small heat shock proteins.
abstract: Abnormal phosphorylation contributes to the formation of neurofibrillary tangles in Alzheimer's disease (AD), but may play other signaling roles during AD pathogenesis. In this study, we employed IMAC followed by LC-MS/MS to identify phosphopeptides from eight individual AD and eight age-matched control postmortem human brain tissues. Using this approach, we identified 5569 phosphopeptides in frontal cortex across all 16 cases in which phosphopeptides represented 80% of all peptide spectral counts collected following IMAC enrichment. Marker selection identified 253 significantly altered phosphopeptides by precursor intensity, changed by at least 1.75-fold relative to controls, with an empirical false discovery rate below 7%. Approximately 21% of all significantly altered phosphopeptides in AD tissue were derived from tau. Of the other 142 proteins hyperphosphorylated in AD, membrane, synapse, cell junction, and alternatively spliced proteins were overrepresented. Of these, we validated differential phosphorylation of HSP 27 (HSPB1) and crystallin-alpha-B (CRYAB) as hyperphosphorylated by Western blotting. We further identified a network of phosphorylated kinases, which coenriched with phosphorylated small HSPs. This supports a hypothesis that a number of kinases are regulating and/or regulated by the small HSP folding network.
authors.affiliation: Department of Biochemistry, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Dammer
authors.affiliation: Department of Biochemistry, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Lee
authors.affiliation: Department of Biochemistry, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Duc M
authors.initials: DM
authors.lastname: Duong
authors.affiliation: Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Marla
authors.initials: M
authors.lastname: Gearing
authors.affiliation: Department of Neurology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: James J
authors.initials: JJ
authors.lastname: Lah
authors.affiliation: Department of Neurology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Allan I
authors.initials: AI
authors.lastname: Levey
authors.affiliation: Department of Biochemistry, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.|Department of Neurology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322.
authors.forename: Nicholas T
authors.initials: NT
authors.lastname: Seyfried
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D001923:Brain Chemistry; D002846:Chromatography, Affinity; D005260:Female; D050888:Heat-Shock Proteins, Small / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008297:Male; D010748:Phosphopeptides / Q000032:analysis / Q000378:metabolism; D010766:Phosphorylation; D060066:Protein Interaction Maps; D011494:Protein Kinases / Q000032:analysis / Q000378:metabolism*; D040901:Proteomics; D053719:Tandem Mass Spectrometry; D016875:tau Proteins / Q000032:analysis / Q000378:metabolism
chemical_list: D050888:Heat-Shock Proteins, Small; D010748:Phosphopeptides; D016875:tau Proteins; D011494:Protein Kinases
keywords: IMAC; MS; Neurodegeneration; Proteostasis; Systems biology