|
|
||||||||
CALL FOR PAPERS
Protein and Vesicle Trafficking, Cytoskeleton
1Department of Physiology, University of Extremadura, Cáceres, Spain; and 2Department of Physiology, University of Cambridge, Cambridge, United Kingdom
Submitted 13 May 2004 ; accepted in final form 4 September 2004
We recently reported that store-operated Ca2+ entry (SOCE) in nonexcitable cells is likely to be mediated by a reversible interaction between Ca2+ channels in the plasma membrane and the endoplasmic reticulum, a mechanism known as "secretion-like coupling." As for secretion, in this model the actin cytoskeleton plays a key regulatory role. In the present study we have explored the involvement of the secretory proteins synaptosome-associated protein (SNAP-25) and vesicle-associated membrane protein (VAMP) in SOCE in pancreatic acinar cells. Cleavage of SNAP-25 and VAMPs by treatment with botulinum toxin A (BoNT A) and tetanus toxin (TeTx), respectively, effectively inhibited amylase secretion stimulated by the physiological agonist CCK-8. BoNT A significantly reduced Ca2+ entry induced by store depletion using thapsigargin or CCK-8. In addition, treatment with BoNT A once SOCE had been activated reduced Ca2+ influx, indicating that SNAP-25 is needed for both the activation and maintenance of SOCE in pancreatic acinar cells. VAMP-2 and VAMP-3 are expressed in mouse pancreatic acinar cells. Both proteins associate with the cytoskeleton upon Ca2+ store depletion, although only VAMP-2 seems to be sensitive to TeTx. Treatment of pancreatic acinar cells with TeTx reduced the activation of SOCE without affecting its maintenance. These findings support a role for SNAP-25 and VAMP-2 in the activation of SOCE in pancreatic acinar cells and show parallels between this process and secretion in a specialized secretory cell type.
synaptosome-associated protein; vesicle-associated membrane protein; pancreatic acinar cells; cytoskeleton; calcium entry
This article has been cited by other articles:
![]() |
G. E. Woodard, G. M. Salido, and J. A. Rosado Enhanced exocytotic-like insertion of Orai1 into the plasma membrane upon intracellular Ca2+ store depletion Am J Physiol Cell Physiol, June 1, 2008; 294(6): C1323 - C1331. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Mukhopadhyay, F. Xu, and P. B. Sehgal Aberrant cytoplasmic sequestration of eNOS in endothelial cells after monocrotaline, hypoxia, and senescence: live-cell caveolar and cytoplasmic NO imaging Am J Physiol Heart Circ Physiol, March 1, 2007; 292(3): H1373 - H1389. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |