Tim Radabaugh

Education:

• Ph.D. Genetics, University of Arizona 2003
• B.S. Computer Science, Grand Canyon College 2000

Achievements:

Professional Experience:

• Research Associate, Arizona Proteomics Consortium 2006-2008
• Research Associate, Proteomics Analysis Laboratory 2004-2005

Research Project:

Asthma project

A chain of published evidence suggests that dog exposure in early life can have a protective effect against developing the asthma phenotype.  We are using a global proteomics approach to look for signatures within the plasma proteomes of children who have and have not been exposed to dogs in early life and who have and have not developed the asthma phenotype later during childhood.  We are using a multipronged approach using mass spectrometry, protein antibody microarrays, and random peptide arrays to look as deeply as we can into the plasma proteome to search for possible patterns which may give us clues to better understand the mechanism by which dog exposure in early life can protect against the asthma phenotype.

Arsenic project

The mechanisms of arsenic mediated ROS production are poorly understood. Here we propose and test a model based on arsenic-iron interactions in ferritin which may lead to the formation of arsenic induced ROS. Ferritin is a 450 kDa iron storage protein with an inner ferric iron core surrounded by a hydrated phosphate shell. Early studies showed that arsenite can induce ferritin synthesis– a process normally triggered by free Fe(II). This finding suggests that arsenite may liberate iron from ferritin by the following redox reaction: As(III) + Fe(III) -> As(V) + Fe(II). The free iron (II) can produce ROS and the resulting arsenate would be available to bind the iron core like its phosphate analog and other oxyanions. Since ferritin exists in almost every cell in the body, this model for arsenic induced ROS represents a major path for arsenic toxicity. Currently we are studying arsenic mediated ROS production in macrophages. Macro-phages are involved in plaque formation in atherosclerosis and contain high levels of ferritin.

Publications:

• Wilson J. A. et al. Media ion composition controls regulatory and virulence response of Salmonella in spaceflight.  PloS ONE 3(12) Epub e3923 Dec 12, 2008.

• Wilson J. A. et al.  Space flight alters bacterial gene expression and virulence and reveals a role for global regulator Hfq. Proc. Natl. Acad. Sci. U S A. Oct 104(41): 16299-304, 2007.

• Haynes, P.A., Miller, S., Radabaugh T., Galligan, M., Breci, L., Rohrbough, J., Hickman, F., Merchant, N.  The wildcat toolbox: a set of perl script utilities for use in peptide mass spectral database searching and proteomics experiments. J. Biomol. Tech. Apr 17(2) 97-102, 2006.

• Frigeri, L.G., Radabaugh, T.R., Haynes, P.A., Hildebrand, M. Identification of proteins from a cell wall fraction of the diatom Thalassiosira pseudonana: insights into silica structure formation.  Mol. Cell Proteomics 5(1): 182-93, 2006.

• Radabaugh, T.R., Sampayo-Reyes, A., Zakharyan, R.A., Aposhian, H.V. Arsenate Reductase II. Purine nucleoside phosphorylase in the presence of dihydrolipoic acid is a route for reduction of arsenate to arsenite in mammalian systems.  Chem. Res. Toxicol. 15: 692-689, 2002.Wilson

• Wildfang, E., Radabaugh, T.R., and Aposhian, H.V. Enzymatic methylation of arsenic compounds. IX. Liver arsenite methyltransferase and arsenate reductase activities in primates.  Toxicology 168: 213-221, 2001.

• Radabaugh, T.R., Aposhian, H.V. Enzymatic reduction of arsenic compounds in mammalian systems: reduction of arsenate by human liver arsenate reductase. Chem. Res. Toxicol. 13: 26-30, 2000.

Abstracts:

• Arsenic-iron interactions in ferritin: A new model for arsenic toxicity. Radabaugh, T.R., Monks, T., Lau, S.S. Presented at the 50^th Annual Meeting of the Society of Toxicology, Washington, D.C., 2011.

• Proteomic Analysis of Human Plasma in Search of Potential Biomarkers Associated with Protection from Asthma. Galligan, M., Breci, L.A., Radabaugh, T.R., Tsaprailis, G., Billheimer, D., Halonen, M., Vercelli, D., Lau S.S. Presented at the 58^th Annual Meeting of the American Society for Mass Spectrometry, Salt Lake City, UT, 2010.

• Proteomic Analysis of Rat and Human Plasma in search of Potential Biomarkers for Type 2 Diabetes. Galligan, M., Kimsey, M., Radabaugh, T., Tsaprailis, G., Link, D., Borges, C., Yassine, H., Henriksen, E., Nelson, R., Stump, S., Lau, S. Presented at the 56^th Annual Meeting of the American Society for Mass Spectrometry, Denver, CO, 2008.

Past and present staff

Present Graduate Students

Ryan Canatsey | Owen Kinsky | Chris Kuhlman | Nick Mastrandrea | Jessica Sapiro | Kevin Xu

Present Postdoctoral Fellow
Tim Radabaugh

Research Associate

Alfred Gallegos

Clinical Faculty Mentee

Hussein Yassine

Current Undergraduate Students

Wesley Cai, Itzel Rojas, Audrey Shi, Kim Tham

Recent Past Staff
Martina Bowen | Jennifer Cohen | Ashley Fisher | Chris Hattan | Mike Kimzey | Matt Labenski | Jean Lord-Garcia