Am J Physiol Cell Physiol Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol (October 16, 2002). doi:10.1152/ajpcell.00333.2002
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
284/2/C547    most recent
00333.2002v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kreft, M.
Right arrow Articles by Zorec, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kreft, M.
Right arrow Articles by Zorec, R.

Articles in PresS, published online ahead of print October 16, 2002
Am J Physiol Cell Physiol, 10.1152/ajpcell.00333.2002
Submitted on July 17, 2002
Accepted on October 15, 2002

Synaptotagmin-I Increases the Probability of Vesicle Fusion at Low [Ca2+] in Pituitary Cells

Marko Kreft1, Vlasta Kuster1, Sonja Grilc1, Marjan Rupnik1, Irina Milisav1, and Robert Zorec1*

1 Inst. Pathophysiology, Medical Faculty, Ljubljana, Slovenia

* To whom correspondence should be addressed. E-mail: robert.zorec{at}mf.uni-lj.si.

Synaptotagmin I, a low-affinity Ca2+-binding protein is thought to serve as the Ca2+ sensor in the release of neurotransmitter. However, functional studies on the Calyx of Held synapse revealed that the rapid release of neurotransmitter requires only ~µM [Ca2+], suggesting that Synaptotagmin I may play a more complex role in determining the high affinity Ca2+-dependence of exocytosis. Here we tested this hypothesis by studying pituitary cells, which possess high- and low-affinity Ca2+-dependent exocytic pathways and express Synaptotagmin I. Using the patch-clamp capacitance measurements to monitor secretion and the acute antisense deletion of Synaptotagmin I from differentiated cells, we show that the rapid and the most Ca2+-sensitive pathway of exocytosis in rat melanotrophs requires Synaptotagmin I. Furthermore, stimulation of the Ca2+-dependent exocytosis by cytosol dialysis with solutions containing 1µM [Ca2+] was completely abolished in the absence of Synaptotagmin I. Similar results were obtained by the preinjection of antibodies against the CAPS (Ca2+-Dependent Activator Protein For Secretion) protein. These results indicate that Synaptotagmin I and CAPS proteins increase the probability of vesicle fusion at low cytosolic [Ca2+].




This article has been cited by other articles:


Home page
 J. Physiol.Home page
N. Vardjan, M. Stenovec, J. Jorgacevski, M. Kreft, and R. Zorec
Elementary properties of spontaneous fusion of peptidergic vesicles: fusion pore gating
J. Physiol., December 15, 2007; 585(3): 655 - 661.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
M. Rupnik, M. Kreft, F. Nothias, S. Grilc, L. K. Bobanovic, L. Johannes, T. Kiauta, P. Vernier, F. Darchen, and R. Zorec
Distinct role of Rab3A and Rab3B in secretory activity of rat melanotrophs
Am J Physiol Cell Physiol, January 1, 2007; 292(1): C98 - C105.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
I. Dudanova, S. Sedej, M. Ahmad, H. Masius, V. Sargsyan, W. Zhang, D. Riedel, F. Angenstein, D. Schild, M. Rupnik, et al.
Important Contribution of {alpha}-Neurexins to Ca2+-Triggered Exocytosis of Secretory Granules
J. Neurosci., October 11, 2006; 26(41): 10599 - 10613.
[Abstract] [Full Text] [PDF]

Home page
 J BiochemHome page
M. Fukuda and A. Yamamoto
Effect of Forskolin on Synaptotagmin IV Protein Trafficking in PC12 Cells
J. Biochem., August 1, 2004; 136(2): 245 - 253.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
M. Kreft, D. Krizaj, S. Grilc, and R. Zorec
Properties of Exocytotic Response in Vertebrate Photoreceptors
J Neurophysiol, July 1, 2003; 90(1): 218 - 225.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 1976 by the American Physiological Society.