Valarie A. Barr, Ph.D.

Valarie A. Barr, Ph.D.
Staff Scientist Facility Head
Head, Microscopy Core Facility

Dr. Barr is head of the LCMB Microscopy Core, which is a light microscopy facility for confocal and super resolution microscopy, open to scientists at the National Cancer Institute. The Core instruments include a Leica SP8 laser scanning confocal microscope, a Nikon total internal reflection fluorescence (TIRF) microscope, and a spinning disk confocal microscope that can perform rapid live cell imaging. The Core provides access to cutting-edge technology and training on the Core's instruments as well as expert assistance with experimental design. In addition, Dr. Barr also carries out independent research on signal transduction in T cells.

Areas of Expertise

1) localization microscopy, 2) TIRF microscopy, 3) confocal microscopy, 4) live cell imaging, 5) immunofluorescence, 6) stimulated emission depletion (STED) imaging

Contact Info

Valarie A. Barr, Ph.D.
Center for Cancer Research
National Cancer Institute
Building 37, Room 2035
Bethesda, MD 20892
Ph: 240-760-7463

The Microscopy Core facility provides state-of-the-art equipment, advice and training to researchers with particular expertise in live cell imaging. Most of the research done in the Core facility focuses on the movement of proteins involved in signal transduction pathways. In collaboration with Dr. Samelson, we study the movements of proteins initially found in signaling complexes that form at activated T cell receptors. These studies use a model system where chimeric proteins tagged with variants of green fluorescent protein (GFP) are visualized in Jurkat T cells. These cells are activated either by contact with antibody-coated coverslips or by contact with superantigen-pulsed Raji B cells. Using this system, we have studied the formation of signaling complexes, the movement of proteins involved in reorganization of the actin cytoskeleton, and the trafficking of SLP-76, an important adaptor protein involved in T cell activation.

In addition to Core operations, Dr. Barr does research on the visualization of signaling complexes. Much of this work centers on the immediate responses to T cell receptor activation in T cells using a combination of localization microscopy, live cell imaging, and immunofluorescence.

NIH Scientific Focus Areas:
Cell Biology, Immunology

Selected Recent Publications

  1. Zvezdova E, Lee J, El-Khoury D, Barr V, Akpan I, Samelson L, Love PE.
    Immunol Cell Biol. 92: 721-8, 2014. [ Journal Article ]
  2. Balagopalan L, Barr VA, Kortum RL, Park AK, Samelson LE.
    J Immunol. 190: 3849-53, 2013. [ Journal Article ]
  3. Coussens NP, Hayashi R, Brown PH, Balagopalan L, Balbo A, Akpan I, Houtman JC, Barr VA, Schuck P, Appella E, Samelson LE.
    Mol Cell Biol. 33: 4140-51, 2013. [ Journal Article ]
  4. Sherman E, Barr VA, Samelson LE.
    Methods. 59: 261-9, 2013. [ Journal Article ]
  5. Sherman E, Barr V, Samelson LE.
    Immunol Rev. 251: 21-35, 2013. [ Journal Article ]

Dr. Barr obtained her Bachelor and Master of Science degrees from the University of Illinois. She completed her graduate work at The Johns Hopkins University, Department of Cell Biology and Anatomy and obtained a Ph.D in cell biology in 1994. After a postdoctoral fellowship in the laboratory of Dr. Simean Taylor at the Diabetes Branch in the National  Institute of Diabetes, Digestive and Kidney Diseases, Dr. Barr joined the Laboratory of Cellular and Molecular Biology in the  National Cancer Institute in 2001.



Name Position
Itoro O. Akpan M.S. Research Biologist