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Dennis Brown

Director, MGH Program in Membrane Biology

Program in Membrane Biology/Div of Nephrology
Massachusetts General Hospital
Simches Research Building, Suite 8202
185 Cambridge St.
Boston, MA 02114
Tel: (617) 726-5665
Fax: (617) 643-3182
Email: brown@receptor.mgh.harvard.edu
Web Page: The Brown Lab Page

CSB Webpage: http://csb.mgh.harvard.edu/
4 postdoctoral fellows, 1 graduate student

The Program in Membrane Biology (PMB) in the Center for Systems Biology at the Massachusetts General Hospital brings together investigators from several areas of research related to protein trafficking and cell signaling. The theme of the PMB is to understand how membrane proteins and transport vesicles interact with accessory proteins (e. g., ARFs, GTPases, SNAREs) and with the cytoskeleton (e. g., microtubules, actin, and PDZ proteins) in physiological and pathophysiological conditions. Experimental models used range from in vitro systems using purified proteins and membrane vesicles (endosomes, Golgi, plasma membrane), to transfected cell cultures, to whole animal models including transgenic mice. All projects are interactive and involve cell biological procedures such as confocal and EM-gold immunocytochemistry, real time confocal and TIRF microscopy, membrane fractionation, immunoprecipitation, biotinylation, phosphorylation, pull-down assays, mass spectrometry and fluorescent tracer assays. Molecular procedures include preparation of adenovirus constructs, GST-fusion protein preparation, yeast two-hybrid screening, and real-time PCR. The aim of the Program is to understand how physiologically-relevant processes of fluid and electrolyte transport across epithelia are regulated at the cell and molecular levels.

                Representative projects include; 1) dissecting the mechanism of water channel (aquaporin 2) trafficking in renal epithelial cells in response to vasopressin. A large scale chemical screen on GFP-expressing cultured cells is being used to identify compounds that stimulate aquaporin membrane insertion for potential clinical application; 2) the role of novel splice variants of the vacuolar proton pumping ATPase (V-ATPase), identified by bioinformatics screening of genomic databases, in key cellular functions is being examined; 3) how the V-ATPase functions as an endosomal “pH-sensing protein” that is involved in coat recruitment and trafficking is being dissected; 4) the role of luminal acidification in sperm storage and maturation in the male reproductive tract is being examined, and the role of so-called “epithelial basal cells” in luminal hormonal sensing is under investigation. Acidification of the tubule lumen is required to maintain sperm in an immotile state during storage.

 

 

References:

  • Brown, D., Breton, S., Ausiello, D. A., and Marshansky, V. Sensing, signaling and sorting events in kidney epithelial cell physiology. Traffic 10: 275-284, 2009.
  • Shum, W. W. C., Da Silva, N., McKee, M., Smith, P. J. S., Brown, D., and Breton, S. Epithelial basal cells are luminal hormone sensors. Cell, 135: 1108-1117, 2008.
  • Lu, H. A. J., Sun, T-X., Yi X-H., Bouley, R., McLaughlin, M., Van Hoek, A., and Brown, D. Heat-shock protein 70 (Hsp/Hsc70) is an aquaporin-2 interacting protein and is involved in AQP2 endocytosis. J. Biol. Chem., 282: 28721-28732, 2007.
  • Hurtado-Lorenzo A, Skinner M, El Annan J, Futai M, Sun-Wada GH, Bourgoin S, Casanova J, Wildeman A, Bechoua S, Ausiello DA, Brown D, and Marshansky V. V-ATPase interacts with ARNO and Arf6 in early endosomes and regulates the protein degradative pathway. Nat. Cell Biol. 8: 124-136, 2006.
  • Bouley, R., Hawthorn, G., Russo, L. M., Lin, H. Y., Ausiello, D. A., and Brown, D. 2006. Aquaporin 2 (AQP2) and vasopressin receptor (V2R) endocytosis in kidney epithelial cells: AQP2 is located in “endocytosis-resistant” membrane domains after vasopressin treatment, Biol. Cell. 98: 215-232. 2006.