Current Research:

My research focuses on the protein compositions and functions of the secretory pathway in exocrine pancreas. Isolated primary acinar cells as well as purified subcellular organelles are being studied, focusing on the mechanisms of secretion of digestive enzymes by regulated exocytosis. Currently, we are using state-of-the-art proteomics approaches to develop molecular architecture model of pancreatic zymogen granule membranes (ZGM) including its protein composition, topology, and protein-protein interactions. In the meantime, we are also investigating the functional roles of several newly identified proteins on ZGM including Rab3D, Rab27B and their potential effectors, synaptotagmin-like proteins and myosin Vc.  These studies have led to new hypotheses about the mechanisms of regulated secretion and will increase our understanding of the physiology and path-physiology of exocrine pancreas.

Representative Publication:

Zhang, W., Chen, M., Chen, X., Segura, B.J. and Mulholland, M.W.  Inhibition of pancreatic protein secretion by ghrelin in the rat, J. Physiology. 537(1): 231-236, 2001

Chen, X., Edwards, J., Logsdon, C.D., Ernst, S.A. and Williams, J.A.  Dominant negative Rab3D inhibits amylase release from mouse pancreatic acini, J. Biol. Chem. 277: 18002-18009, 2002

Chen, X., Ernst, S.A. and Williams, J.A.  Dominant negative Rab3D mutants reduce GTP-bound endogenous Rab3D in pancreatic acini, J. Biol. Chem. 278: 50053-50060, 2003

Li, C., Chen, X., and Williams, J.A.  Regulation of CCK-induced amylase release by protein kinase C delta in rat pancreatic acinar cells, Am. J. Physiol. 287(4): G764-G771, 2004 

Chen, X., Li, C., Izumi T., Ernst, S.A., Andrews, P. C. and Williams, J.A.  Rab27b localizes to ZG membrane and regulates acinar secretion, Biochem. Biophys. Res. Commun.  323:1156-1161, 2004

Chen, X., Walker, A. K., Strahler, J. R., Simon, E. S., Volk, S. L., Nelson, B. B., Hurley, M. C., Ernst, S.A., Williams, J.A., and Andrews, P. C.  Organellar proteomics: analysis of pancreatic zymogen granule membranes.  Molecular & Cellular Proteomics  5(2): 306-12, 2006

Chen, X., and Andrews, P. C. Proteomics analysis of pancreatic zymogen granule membrane. In:  Methods in Molecular Biology, edited by Jean Rossier, Humana Press, In press

Zhang, W., Evans, E., Jerdeva, G., Chen, X., Hamm-Alvarez, S.F. and Okamoto, C.T.  Direct interaction between Rab3D and the polymeric immunoglobulin receptor may regulate its trafficking through regulated secretory vesicles in lacrimal gland acinar cells. Am. J. Physiol.  Revision

Chen, X., Simon, E., Williams, J.A., and Andrews, P. C.  Global topology analysis of pancreatic zymogen granule membranes.  Molecular & Cellular Proteomics   submitted

Zhang, W., Evans, E., Jerdeva, G., Chen, X., Hamm-Alvarez, S.F. and Okamoto, C.T.  Direct interaction between Rab3D and the polymeric immunoglobulin receptor may regulate its trafficking through regulated secretory vesicles in lacrimal gland acinar cells. Am. J. Physiol.  In press

Chen, X., Simon, E., Williams, J.A., and Andrews, P. C.  Global topology analysis of pancreatic zymogen granule membranes.  Molecular & Cellular Proteomics   revision

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