The major interest of the laboratory concerns the mechanisms underlying

Ca2+-dependent exocytosis.The molecular mechanismsunderlying secretion of prepackaged hormones and neurotransmitters are being studied using primary adrenal chromaffin cells and PC12 cells in tissue culture as model systems. Biochemical, electrophysiological, and molecular genetic techniques are being employed to study the effects of specific proteins on regulated secretion. Research concerns the roles of the Rab3a/Rabphilin3a/Rim pathway, 'SNARE' proteins (syntaxin, vamp, SNAP-25, NSF), and the latrotoxin receptor in the secretory pathway. We are also using a powerful optical technique, total internal reflection fluorescence microscopy (TIRFM), to study granule motion and biochemical events immediately adjacent to the plasma membrane during exocytosis. (Image: combined DIC and fluorescence of chromaffin cells with one cell transiently-expressing ANP-GFP in secretory granules)

TIRFM movie of exocytosis of secretory granules labeled with VAMP-eGFP

in bovine chromaffin cells. Exocytosis is stimulated by a nicotinic cholinergic agonist. The first exocytotic event occurs at 9 sec. View