Cell and Developmental Biology University of Michigan

Research

Research in the area of regulation of vesicle/granule secretion in exocrine, endocrine and neurosecretory cells.

Current research is involved with basic mechanisms involved in regulation of exocrine and endocrine secretion, particularly with regard to vesicular transport and fusion. In collaboration with Dr. Edward Stuenkel (Molecular & integrative Physiology), my laboratory focuses on morphological aspects of regulation of insulin secretion and neurosecretion (chomaffin cells) at the plasma membrane, including interactions of small G-proteins (e.g., Rab 27A) and other modulators (e.g., tomosyn) with the t-SNARE syntaxin 1A. Methods involve confocal microscopy coupled with immunocytochemistry of expressed proteins, fluorescence recovery after photobleaching (FRAP), fluorescence resonance energy transfer (FRET), and other optical techniques.

In collaboration with Dr. John Williams (Molecular & integrative Physiology), we localize small G-proteins and other constituents thought to be involved in regulated granule secretion of digestive enzymes in pancreatic exocrine cells and purified zymogen granules, and study morphological aspects of regulation of pancreatic growth, and alterations accompanying induced pancreatitis.

• Bradley Nelson
  Research Lab Technician

Publications

Representative Publications

• *Lui, J., S.A. Ernst*, S.E. Gladycheva, Y.Y. Lee, S.I. Lentz, C.S. Ho, Q. Li, and E.L. Stuenkel. 2004. Fluorescence resonance energy transfer reports properties of syntaxin1a interaction with Munc18-1 in vivo . J. Biol. Chem. 279:55924-55936. (*Both authors contributed equally to this work)
• Chen, X., A.K. Walker, J.R. Strahler, E.S. Simon, S.L. Tomanicek-Volk, B.B. Nelson, M.C. Hurley, S.A. Ernst, J.A. Williams, and P.C. Andrews. 2006. Organellar Proteomics. Analysis of pancreatic zymogen granule membranes . Mol. Cellular Proteomics 5:306-312.  (Journal Cover Illustration)
• Gladycheva S.E., A.D. Lam, J. Liu, M. D'Andrea-Merrins, O. Yizhar, S.I. Lentz, U. Ashery, S.A. Ernst, and E.L. Stuenkel. 2007. Receptor-mediated regulation of tomosyn-syntaxin 1A interactions in bovine adrenal chromaffin cells . J Biol Chem. 282:22887-99.
• Sabbatini, M.E., X. Chen, S.A Ernst, and J.A Williams. 2008. Rap1 activation plays a regulatory role in pancreatic amylase secretion . J. Biol. Chem. 283:23884-23894.
• Ji B, S. Gaiser, X. Chen, S.A. Ernst, and C.D. Logsdon. 2009. Intracellular trypsin induces pancreatic acinar cell death but not NF-kappaB activation. J. Biol. Chem. 26;284:17488-98
• Chen, X., M.D. Sans, J.R. Strahler, A. Karnovsky, S.A. Ernst, G. Michailidis, P.C. Andrews, and J.A. Williams. 2010. Quantitative organellar proteomics analysis of rough endoplasmic reticulum from normal and acute pancreatitis rat pancreas . J. Proteome Res. 9:885-896.
• Gurda, G.T., S.J. Crozier, B. Ji, S.A. Ernst, C.D. Logsdon, B.A. Rothermel, and J.A. Williams. 2010. Regulator of calcineurin 1 (Rcan1) controls growth plasticity of adult pancreas. Gastroenterol. 139:609-619.
• Lam, A.D., S. Ismal, R. Wu, O. Yizhar, S.A. Ernst, and E. L. Stuenkel. 2010. Mapping dynamic protein interactions to insulin secretory granule behavior with TIRF-FRET . Biophys. J. 99:1311-1320.
• Sabbatini M.E., Y. Bi, B. Ji, S.A. Ernst, and J.A. Williams. 2010. CCK activates RhoA and Rac1 differentially through Galpha13 and Galpha q in mouse pancreatic acini. Am. J. Physiol. Cell Physiol. 298:C592-601.