title: A novel monoclonal antibody DC63 reveals that inhibitor 1 of protein phosphatase 2A is preferentially nuclearly localised in human brain.
abstract: Abnormal phosphorylation of tau protein represents one of the major candidate pathological mechanisms leading to Alzheimer's disease (AD) and related tauopathies. Altered phosphorylation status of neuronal tau protein may result from upregulation of tau-specific kinases or from inhibition of tau-specific phosphatases. Increased expression of the protein inhibitor 1 of protein phosphatase 2A (I1PP2A) could therefore indirectly regulate the phosphorylation status of tau. As an important step towards elucidation of the role of I1PP2A in the physiology and pathology of tau phosphorylation, we developed a novel monoclonal antibody, DC63, which recognizes I1PP2A. Specificity of the antibody was examined by mass spectrometry and Western blot. This analysis supports the conclusion that the antibody does not recognize any of the other proteins of the 9-member leucine-rich acidic nuclear phosphoprotein family to which I1PP2A belongs. Immunoblot detection revealed that the inhibitor I1PP2A is expressed throughout the brain, including the hippocampus, temporal cortex, parietal cortex, subcortical nuclei and brain stem. The cerebellum displayed significantly higher levels of expression of I1PP2A than was seen elsewhere in the brain. Imunohistochemical analysis of normal human brain showed that I1PP2A is expressed in both neurons and glial cells and that the protein is preferentially localized to the nucleus. We conclude that the novel monoclonal antibody DC63 could be successfully employed as a mass spectrometry-validated molecular probe that may be used for in vitro and in vivo qualitative and quantitative studies of physiological and pathological pathways involving I1PP2A.
authors.affiliation: Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska 9, 845 10 Bratislava, Slovak Republic.
authors.forename: Branislav
authors.initials: B
authors.lastname: Kovacech
authors.forename: Eva
authors.initials: E
authors.lastname: Kontsekova
authors.forename: Norbert
authors.initials: N
authors.lastname: Zilka
authors.forename: Pavol
authors.initials: P
authors.lastname: Novak
authors.forename: Rostislav
authors.initials: R
authors.lastname: Skrabana
authors.forename: Peter
authors.initials: P
authors.lastname: Filipcik
authors.forename: Khalid
authors.initials: K
authors.lastname: Iqbal
authors.forename: Michal
authors.initials: M
authors.lastname: Novak
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D015153:Blotting, Western; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D020869:Gene Expression Profiling; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010455:Peptides / Q000737:chemistry; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016601:RNA-Binding Proteins; D017385:Sequence Homology; D014020:Tissue Extracts
chemical_list: C087425:ANP32A protein, human; D000911:Antibodies, Monoclonal; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010455:Peptides; D011506:Proteins; D016601:RNA-Binding Proteins; D014020:Tissue Extracts