Barbara  A. Christy,  Ph.D.

Associate Professor

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Profile and Contact Information | Research | Laboratory

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RESEARCH

Research Program

Our laboratory is interested in proteins involved in control of mammalian cell growth and differentiation. A major project in the laboratory focuses on the Id proteins. Id proteins are small helix-loop-helix (HLH) proteins which are thought to act as dominant-negative regulators of transcription factors which regulate cellular differentiation and growth in a number of cell lineages. Id proteins interact with these and other regulatory proteins to affect their activities, and have recently been implicated in tumorigenesis and angiogenesis. We are investigating the mechanisms of action of the four mammalian Id proteins (Id1-4). We have identified proteins which interact with these proteins and thus represent targets for Id protein regulation. On the other hand, some of the interacting proteins represent proteins which may regulate Id protein activities. One such protein, JAB1, is a subunit of a large protein complex called the COP9 signalosome. This complex is implicated in cell cycle regulation and cell signaling. We are currently investigating the consequences of the Id-JAB1 interaction in cells. Our long-term goal is to define the importance of these and other regulatory proteins in the control of growth and differentiation, and to devise ways of controlling these activities.

Selected Publications

1. Melnikova IN, Bounpheng M, Schatteman GC, Gilliam D, and Christy B: (1999) Differential biological activities of mammalian Id proteins in muscle cells. Exp Cell Res. 247: 94-104.
2. Chen H, Weng YC, Schatteman GC, Sanders L, Christy RJ, and Christy BA: (1999) Expression of the dominant-negative regulator Id4 is induced during adipocyte differentiation. Biochem Biophys Res Commun. 256: 614-9.
3. Bounpheng MA, Melnikova IN, Dimas JJ, and Christy BA: (1999) Identification of a novel transcriptional activity of mammalian Id proteins. Nucleic Acids Res. 27: 1740-6.
4. Bounpheng MA, Dimas JJ, Dodds SG, and Christy BA: (1999) Degredation of Id proteins by the ubiquitin-proteasome pathway. FASEB J. 13: 2257-64.
5. Thatikunta P, Qin W, Christy BA, Tennekoon GI, and Rutkowski JL: (1999) Reciprocal Id expression and myelin gene regulation in Schwann cells. Mol Cell Neurosci. 14: 519-28.
6. Bounpheng MA, Melnikova IN, Dodds SG, Chen H, Copeland NG, Gilbert DJ, Jenkins NA, and Christy BA: (2000) Characterization of the mouse JAB1 cDNA and protein. Gene 242: 41-50.
7. Johansson MH, Bieberich C, Kase-Sjostrom A, Yoshioka T, Hoglund E, Christy BA, Scangos G, Karre K, Jay G, and Hoglund P: (2000) Differential effects on T cell and NK cell development by tissue-specific expression of H-2D(d) transgene. Eur J Immunol. 30: 525-33.
8. Bounpheng MA, Morrish TA, Dodds SG, and Christy BA: (2000) Negative regulation of selected bHLH proteins by eHAND. Exp Cell Res. 257: 320-31.
9. Schatteman GC, Hanlon HD, Jiao C, Dodds SG, and Christy BA: (2000) Blood-derived angioblasts accelerate blood-flow restoration in diabetic mice. J Clin Invest. 106: 571-8.
10. Christy BA: (2001) A role for an alternatively spliced Id3 isoform in vascular lesions? (Invited Editorial) Arterioscler Thromb Vasc Biol. 21: 727-8.
11. Gooch JL, Christy B, and Yee D: (2002) STAT6 mediates interleukin-4 growth inhibition in human breast cancer cells. Neoplasia 4: 324-31.
12. Christy BA: (2003) What are Id proteins and why should we care? (Invited Review) In: Recent Research Developments in Biophysics and Biochemistry, Vol. 2. Recent Res Dev Biophys Biochem. 3: 815-831.
13. Berse M, Bounpheng M, Huang X, Christy B, Pollmann C, and Dubiel W: (2004) Ubiquitin-dependent degradation of Id1 and Id3 is mediated by the COP9 signalosome. J Mol Biol. 343: 361-70.