title: Mass spectrometric phosphoproteome analysis of HIV-infected brain reveals novel phosphorylation sites and differential phosphorylation patterns.
abstract: OBJECTIVE
  To map the phosphoproteome and identify changes in the phosphorylation patterns in the HIV-infected and uninfected brain.
  
  
  METHODS
  Parietal cortex from individuals with and without HIV infection were lysed and trypsinized. The peptides were labeled with iTRAQ reagents, combined, phospho-enriched by titanium dioxide chromatography, and analyzed by LC-MS/MS with high resolution.
  
  
  RESULTS
  Our phosphoproteomic workflow resulted in the identification of 112 phosphorylated proteins and 17 novel phosphorylation sites in all the samples that were analyzed. The phosphopeptide sequences were searched for kinase substrate motifs, which revealed potential kinases involved in important signaling pathways. The site-specific phosphopeptide quantification showed that peptides from neurofilament medium polypeptide, myelin basic protein, and 2'-3'-cyclic nucleotide-3' phosphodiesterase have relatively higher phosphorylation levels during HIV infection.
  
  
  CONCLUSIONS
  This study has enriched the global phosphoproteome knowledge of the human brain by detecting novel phosphorylation sites on neuronal proteins and identifying differentially phosphorylated brain proteins during HIV infection. Kinases that lead to unusual phosphorylations could be therapeutic targets for the treatment of HIV-associated neurocognitive disorders.
authors.affiliation: Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.|The Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Lerna
authors.initials: L
authors.lastname: Uzasci
authors.affiliation: Clinical Neurosciences Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Sungyoung
authors.initials: S
authors.lastname: Auh
authors.affiliation: The Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Cotter
authors.affiliation: Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Avindra
authors.initials: A
authors.lastname: Nath
mesh_terms: D001921:Brain / Q000378:metabolism* / Q000821:virology; D018792:Encephalitis, Viral / Q000378:metabolism* / Q000821:virology; D015658:HIV Infections / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D010750:Phosphoproteins / Q000032:analysis* / Q000378:metabolism; D010766:Phosphorylation; D040901:Proteomics
chemical_list: D010750:Phosphoproteins
keywords: Drug target; HIV-associated neurocognitive disorders; Phosphorylation; Protein kinase A; Proteomics