Physiology Commons^™

Synaptotagmin C2b Ca2+-Binding Loops Impose Distinct Exocytosis Phenotypes, Michael W. Schmidtke

Wayne State University Theses

Regulated exocytosis from chromaffin cells in the adrenal medulla plays a critical role in maintaining organismal homeostasis. In the absence of stress, these cells release physiologically relevant substances into the blood stream only in limited quantities, whereas stressful conditions result in a rapid deluge of signaling molecules used, for example, to increase heart rate and pain tolerance. Although the cellular mechanisms governing the switch from low-level to stress-induced secretion are not well understood, recent evidence has implicated the exocytotic Ca2+-sensing protein Synaptotagmin (Syt) in this role.

Two isoforms of Syt are expressed in chromaffin cells (Syt-1 and Syt-7), and each …

Regulation Of Nkcc2 Trafficking By Vesicle Fusion Proteins Vamp2 And Vamp3 In The Thick Ascending Limb, Paulo Sebastian Caceres Puzzella

Wayne State University Dissertations

The thick ascending limb (TAL) in the kidney regulates extracellular fluid volume and blood pressure. The Na/K/2Cl cotransporter NKCC2 plays a central role in NaCl absorption by the TAL and blood pressure. NKCC2 trafficking to the apical membrane is a major mechanism to control NKCC2 activity. However, little is known about the proteins that mediate NKCC2 trafficking. Inhibition of the vesicle fusion proteins VAMP2 and VAMP3 blunts the increase in surface NKCC2 expression and NaCl absorption in response to stimulation by cAMP. In other cells, VAMPs mediate fusion of exocytic vesicles with the plasma membrane. Whether VAMP2 and VAMP3 mediate …