| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
J Biol Chem, Vol. 273, Issue 9, 5020-5025, February 27, 1998
From the Department of Physiology, Emory University School of
Medicine, Atlanta, Georgia 30322
Thapsigargin is a specific and potent inhibitor
of sarco/endoplasmic reticulum Ca2+-ATPases. However,
in whole rat brain microsomes, 1 µM thapsigargin had no
significant effect on the 10-min time course of
ATP-dependent Ca2+ uptake in the absence of the
luminal Ca2+ chelator oxalate. In contrast, 50 mM oxalate resolved a thapsigargin-sensitive Ca2+ uptake rate (IC50
Luminal Ca2+ Protects against Thapsigargin Inhibition
in Neuronal Endoplasmic Reticulum
1 nM
thapsigargin) five times that of a thapsigargin-insensitive rate. This
remaining ~20% of the total ATP-dependent accumulation was insensitive to thapsigargin (up to 10 µM), slightly
less sensitive to vanadate inhibition, and unresponsive to 5 µM inositol 1,4,5-trisphosphate or 10 mM
caffeine. Measuring both 12-min Ca2+ uptake and initial
Ca2+ uptake rates, the apparent thapsigargin sensitivity
increased as oxalate concentrations increased from 10 to 50 mM, corresponding to a range of luminal free
Ca2+ concentrations of ~300 down to 60 nM.
Addition of oxalate during steady-state 45Ca accumulation
rapidly resolved the aforementioned thapsigargin sensitivity. These
results strongly suggest that luminal Ca2+ may protect a
large portion of neuronal endoplasmic reticulum Ca2+ pumps
against thapsigargin inhibition. Although high [Ca2+] has
been previously shown to protect against thapsigargin inhibition in
several reticular membrane preparations, our results suggest that
luminal Ca2+ alone is responsible for mediating this effect
in neurons.
Copyright © 1998 by The American Society for Biochemistry and Molecular Biology, Inc.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  S. Lutsenko, N. L. Barnes, M. Y. Bartee, and O. Y. Dmitriev Function and Regulation of Human Copper-Transporting ATPases Physiol Rev, July 1, 2007; 87(3): 1011 - 1046. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Pelled, E. Lloyd-Evans, C. Riebeling, M. Jeyakumar, F. M. Platt, and A. H. Futerman Inhibition of Calcium Uptake via the Sarco/Endoplasmic Reticulum Ca2+-ATPase in a Mouse Model of Sandhoff Disease and Prevention by Treatment with N-Butyldeoxynojirimycin J. Biol. Chem., August 8, 2003; 278(32): 29496 - 29501. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X.-J. Meng, R. T. Timmer, R. B. Gunn, and R. F. Abercrombie Separate entry pathways for phosphate and oxalate in rat brain microsomes Am J Physiol Cell Physiol, June 1, 2000; 278(6): C1183 - C1190. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Korkotian, A. Schwarz, D. Pelled, G. Schwarzmann, M. Segal, and A. H. Futerman Elevation of Intracellular Glucosylceramide Levels Results in an Increase in Endoplasmic Reticulum Density and in Functional Calcium Stores in Cultured Neurons J. Biol. Chem., July 30, 1999; 274(31): 21673 - 21678. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. J. Rogue, J.-P. Humbert, A. Meyer, S. Freyermuth, M.-M. Krady, and A. N. Malviya cAMP-dependent protein kinase phosphorylates and activates nuclear Ca2+-ATPase PNAS, August 4, 1998; 95(16): 9178 - 9183. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Fernandez-Belda, M.-I. Fortea, and F. Soler Testing the Versatility of the Sarcoplasmic Reticulum Ca2+-ATPase Reaction Cycle When p-Nitrophenyl Phosphate Is the Substrate J. Biol. Chem., March 9, 2001; 276(11): 7998 - 8004. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| All ASBMB Journals | Molecular and Cellular Proteomics |
| Journal of Lipid Research | ASBMB Today |
