Barium and Calcium Stimulate Secretion from Digitonin-Permeabilized Bovine Adrenal Chromaffin Cells by Similar Pathways

We compared the characteristics of secretion stimulated by EGTA-buffered Ba 2+ - and Ca 2+ -containing solutions in digitonin-permeabilized bovine adrenal chromaffin cells. Half-maximal secretion occurred at approximately 100 Μ M Ba 2+ or 1 Μ M Ca 2+ . Ba 2+ -stimulated release was not due to release of sequestered intracellular Ca 2+ because at a constant free Ba 2+ concentration, increasing unbound EGTA did not diminish the extent of release due to Ba 2+ . The maximal extents of Ba 2+ - and Ca 2+ -dependent secretion in the absence of MgATP were identical. MgATP enhanced Ba 2+ -induced secretion to a lesser extent than Ca 2+ -induced secretion. Half-maximal concentrations of Ba 2+ and Ca 2+ , when added together to cells, yielded approximately additive amounts of secretion. Maximal concentrations of Ba 2+ and Ca 2+ when added together to cells for 2 or 15 min were not additive. Tetanus toxin inhibited Ba 2+ - and Ca 2+ -dependent secretion to a similar extent. Ba 2+ , unlike Ca 2+ , did not activate polyphosphoinositide-specific phospholipase C. These data indicate that (1) Ba 2+ directly stimulates exocytosis, (2) Ba 2+ -induced secretion is stimulated to a lesser extent than Ca 2+ -dependent secretion by MgATP, (3) Ba 2+ and Ca 2+ use similar pathways to trigger exocytosis, and (4) exocytosis from permeabilized cells does not require activation of polyphosphoinositide-specific phospholipase C.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66323/1/j.1471-4159.1992.tb09771.x.pd

Syntaxin 16 is a master recruitment factor for cytokinesis

Recently it was shown that both recycling endosome and endosomal sorting complex required for transport (ESCRT) components are required for cytokinesis, in which they are believed to act in a sequential manner to bring about secondary ingression and abscission, respectively. However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated. The trafficking of membrane vesicles between different intracellular organelles involves the formation of soluble N-ethylmalei­mide–sensitive factor attachment protein receptor (SNARE) complexes. Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear. Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome–associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked

Protein kinase C and clostridial neurotoxins affect discrete and related steps in the secretory pathway

1. The effects on catecholamine secretion of activation of protein kinase C and clostridial neurotoxins were examined in digitonin-permeabilized bovine adrenal chromaffin cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44281/1/10571_2004_Article_BF00711564.pd

Control of exocytosis from adrenal chromaffin cells

1. Calcium-dependent exocytosis of catecholamines from intact and digitonin-permeabilized bovine adrenal chromaffin cells was investigated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44286/1/10571_2004_Article_BF00711168.pd

An aPKC-Exocyst Complex Controls Paxillin Phosphorylation and Migration through Localised JNK1 Activation

The exocyst/aPKC complex controls the spatiotemporal activation of the kinases JNK and ERK at the leading edge of migrating cells and thereby controls the dynamic behaviour of the adhesion protein paxillin during cell migration

Calcium promotes the accumulation of polyphosphoinositides in intact and permeabilized bovine adrenal chromaffin cells

1. Because cellular pools of phosphatidylinositol phosphate and phosphatidylinositol bisphosphate turn over rapidly during phospholipase C stimulation, the continuing production of inositol phosphates requires continuing synthesis from phosphatidylinositol of the polyphosphoinositides. In the present study in adrenal chromaffin cells, we examined the effects of nicotinic stimulation and depolarization in intact cells and micromolar Ca 2+ in permeabilized cells on the levels of labeled polyphosphoinositides. We compared the effects to muscarinic stimulation in intact cells and GTP γ S in permeabilized cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44280/1/10571_2004_Article_BF00713279.pd

Vesicle Docking to the Spindle Pole Body Is Necessary to Recruit the Exocyst During Membrane Formation in Saccharomyces cerevisiae

The meiosis II outer plaque (MOP) acts a vesicle tethering complex that is a site for de novo membrane formation. Novel mutants in a MOP protein reveal that interaction of vesicles with the MOP surface is required to recruit a second tethering complex, the exocyst, to the vesicles, suggesting a mechanism by which the MOP promotes vesicle fusion

Dual role of the exocyst in AMPA receptor targeting and insertion into the postsynaptic membrane

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102104/1/emboj7601065.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102104/2/emboj7601065-sup-0001.pd