Michael A. Freitas Ph.D.

Research Assistant Professor
Department of Molecular Virology, Immunology and Medical Genetics

Research Program:

Our group has developed extensive expertise in the field of clinical/translational proteomics, biomarker discovery/validation and bioinformatics for mass spectrometry based proteomics. Our work focuses on the determination of side chain modifications of proteins important in Chromatin Remodeling and relating these modifications to aberrant cellular function in cancer.

Selected Publications:

Xu H, Freitas MA A mass accuracy sensitive probability based scoring algorithm for database searching of tandem mass spectrometry data. BMC Bioinformatics. 2007 Apr 20;8:133.

Su X, Ren C, Freitas MA. Mass spectrometry-based strategies for characterization of histones and their post-translational modifications. Expert Rev Proteomics. 2007 Apr;4(2):211-25.

Tu S, Bulloch EM, Yang L, Ren C, Huang WC, Hsu PH, Chen CH, Liao CL, Yu HM, Lo WS, Freitas MA, Tsai MD. Identification of histone demethylases in Saccharomyces cerevisiae. J Biol Chem. 2007 May 11;282(19):14262-71.

Tsubota T, Berndsen CE, Erkmann JA, Smith CL, Yang L, Freitas MA, Denu JM, Kaufman PD. Histone H3-K56 acetylation is catalyzed by histone chaperone-dependent complexes. Mol Cell. 2007 Mar 9;25(5):703-12. Epub 2007 Feb 22.

Knapp AR, Ren C, Su X, Lucas DM, Byrd JC, Freitas MA, Parthun MR. Quantitative profiling of histone post-translational modifications by stable isotope labeling. Methods. 2007 Mar;41(3):312-9.

Su X, Zhang L, Lucas DM, Davis ME, Knapp AR, Green-Church KB, Marcucci G, Parthun MR, Byrd JC, Freitas MA.

Histone H4 acetylation dynamics determined by stable isotope labeling with amino acids in cell culture and mass spectrometry.

Anal Biochem. 2007 Apr 1;363(1):22-34.

Su X, Jacob NK, Amunugama R, Lucas DM, Knapp AR, Ren C, Davis ME, Marcucci G, Parthun MR, Byrd JC, Fishel R, Freitas MA. Liquid chromatography mass spectrometry profiling of histones. J Chromatogr B Analyt Technol Biomed Life Sci. 2007 May 1;850(1-2):440-54.

Zhang L, Su X, Liu S, Knapp AR, Parthun MR, Marcucci G, Freitas MA. Histone H4 N-terminal acetylation in Kasumi-1 cells treated with depsipeptide determined by acetic acid-urea polyacrylamide gel electrophoresis, amino acid coded mass tagging, and mass spectrometry. J Proteome Res. 2007 Jan;6(1):81-8.

Ren C, Zhang L, Freitas MA, Ghoshal K, Parthun MR, Jacob ST. Peptide mass mapping of acetylated isoforms of histone H4 from mouse lymphosarcoma cells treated with histone deacetylase (HDACs) inhibitors. J Am Soc Mass Spectrom. 2005 Oct;16(10):1641-53.

Ye J, Ai X, Eugeni EE, Zhang L, Carpenter LR, Jelinek MA, Freitas MA, Parthun MR. Histone H4 lysine 91 acetylation a core domain modification associated with chromatin assembly. Mol Cell. 2005 Apr 1;18(1):123-30.

Freitas MA, Sklenar AR, Parthun MR. Application of mass spectrometry to the identification and quantification of histone post-translational modifications. J Cell Biochem. 2004 Jul 1;92(4):691-700.

Zhang L, Freitas MA, Wickham J, Parthun MR, Klisovic MI, Marcucci G, Byrd JC. Differential expression of histone post-translational modifications in acute myeloid and chronic lymphocytic leukemia determined by high-pressure liquid chromatography and mass spectrometry. J Am Soc Mass Spectrom. 2004 Jan;15(1):77-86.

Zhang L, Eugeni EE, Parthun MR, Freitas MA. Identification of novel histone post-translational modifications by peptide mass fingerprinting. Chromosoma. 2003 Aug;112(2):77-86.