title: Elevated MARK2-dependent phosphorylation of Tau in Alzheimer's disease.
abstract: The appearance of neurofibrillary tangles (NFT), one of the major hallmarks of Alzheimer's disease (AD), is most likely caused by inappropriate phosphorylation and/or dephosphorylation of tau, eventually leading to the accumulation of NFTs. Enhanced phosphorylation of tau on Ser(262) is detected early in the course of the disease and may have a role in the formation of tangles. Several kinases such as microtubule-affinity regulating kinase (MARK), protein kinase A, calcium calmodulin kinase II, and checkpoint kinase 2 are known to phosphorylate tau on Ser(262) in vitro. In this study, we took advantage of the in situ proximity ligation assay to investigate the role of MARK2, one of the four MARK isoforms, in AD. We demonstrate that MARK2 interacts with tau and phosphorylates tau at Ser(262) in stably transfected NIH/3T3 cells expressing human recombinant tau. Staurosporine, a protein kinase inhibitor, significantly reduced the interaction between MARK2 and tau, and also phosphorylation of tau at Ser(262). Furthermore, we observed elevated interactions between MARK2 and tau in post-mortem human AD brains, compared to samples from non-demented elderly controls. Our results from transfected cells demonstrate a specific interaction between MARK2 and tau, as well as MARK2-dependent phosphorylation of tau at Ser(262). Furthermore, the elevated interactions between MARK2 and tau in AD brain sections suggests that MARK2 may play an important role in early phosphorylation of tau in AD, possibly qualifying as a therapeutic target for intervention to prevent disease progression.
authors.affiliation: Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Gucci Jijuan
authors.initials: GJ
authors.lastname: Gu
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Harald
authors.initials: H
authors.lastname: Lund
authors.forename: Dan
authors.initials: D
authors.lastname: Sunnemark
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Kvist
authors.forename: Roy
authors.initials: R
authors.lastname: Milner
authors.forename: Sonia
authors.initials: S
authors.lastname: Eckersley
authors.forename: Lars N G
authors.initials: LN
authors.lastname: Nilsson
authors.forename: Karin
authors.initials: K
authors.lastname: Agerman
authors.forename: Ulf
authors.initials: U
authors.lastname: Landegren
authors.forename: Masood
authors.initials: M
authors.lastname: Kamali-Moghaddam
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002461:Cell Line, Transformed; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014162:Transfection; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D016875:tau Proteins; D049452:Green Fluorescent Proteins; D012694:Serine; C094670:MARK2 protein, human; D017346:Protein Serine-Threonine Kinases; D019311:Staurosporine