the life and death of proteins: regulation by ubiquitin and the proteasome

Michael Kashgarian, M.D. Professor of Pathology and Molecular, Cellular, and Developmental Biology Yale University 310 Cedar Street P.O. Box 208023 New Haven, CT 06520-8023 Phone 203.785.2750 FAX 203.785.3348 michael.kashgarian@yale.edu

Our laboratory is focused on the cell biology of ion transporting epithelium in general and in the renal tubule in particular. The structural and functional characteristics transporting epithelia are being studied in a variety of normal, adaptive, and pathologic states. Ultrastructural and confocal microscopy techniques are being used to study adaptive changes in the transporting epithelium along with use of monoclonal antibody and molecular probes to transport and cytoskelatal proteins. These techniques have been used to assess some aspects of the functional characteristics of NaK-ATPase as well as studying cellular biosynthesis, assembly, and polar insertion into the plasma membrane. Additional studies are being directed at the isolation of other transport proteins to study their distribution and function. These include the potassium-proton pump of the colon, CFTR, and vacuolar H-ATPase and the mitochondrial F1Fo ATPase. In addition, studies are underway to investigate the interactions of transport proteins with adaptor molecules and cytoskeletal elements and the role of these interactions in the development and maintenance of cell polarity as well as in functional regulation. A major aspect of our investigation has been directed towards a detailed analysis and understanding of the complex morphologic features, physiologic mechanisms and metabolic processes which are involved in renal cell injury and recovery. The present investigations are designed to determine the cellular and molecular basis of the morphologic and physiologic preservation which accompanies recovery from renal epithelial injury and specifically to investigate the role of adenine nucleotide metabolism in the initiation of renal cellular injury, activation of the stress response and recovery. Studies to investigate the integrity of cell plasma membrane structure and function and how it is affected by ATP depletion are being conducted to determine whether calcium signaling provides a cross link between the cytoskeletal alterations, cellular nucleotides, induction of the stress response and the loss of membrane integrity. The contribution of the stress response via the induction of heat shock proteins is being studied to determine how these proteins may be involved in cytoprotection by stabilizing the cytoskeleton and by recycling of proteins displaced from their correct membrane domains.

Selected Publications

Eickelberg, O., Geibel, J. Seebach, F. Giebisch, G. Kashgarian, M. Potassium induced HSP-72 Expression is Mediated via Rapid Calcium Influx in Renal Epithelial Cells. Am. J. Physiol. 281: F280-287,2001

Aufricht,C., Bidmon, B., Ruffingshofer,D., Regele,H., Herkner,K., Siegel, N.J., Kashgarian, M. Van Why, S.K. Ischemic conditioning prevents Na,K-ATPase dissociation from the cytoskeletal cellular fraction after repeat renal ischemia in rats. Pediatric Res. 51 (6): 722-727,2002

VanWhy, S.K., Mann, A.S., Ardito, T., Thulin, G., Ferris, S., MacLeod, M.A., Kashgarian, M., Siegel, N.J. Hsp 27 Associates with Actin and Limits Injury in Energy Depleted Renal Epithelia. J.Am. Soc. Nephrol. 14 (1): 98-106 2003

. Vicencio A, Bidmon B, Ryu J, Reidy K, Thulin G, Mann A, Gaudio KM, Kashgarian M, Siegel NJ. Develomental expression of Hsp 72 and ischemic tolerance of the immature kidney. Pediatr Nephrol. Feb; 18(2):85-91, 2003

Kale S, Karihaloo A, Clark PR, Kashgarian M, Krause DS, Cantley LG.Bone marrow stem cells contribute to repair of the ischemically injured renal tubule. J Clin Invest. Jul;112(1):42-9, 2003. Epub Jun 16, 2003.

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