|
|
|
|
|
||
|
|||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
Journal of Cell Science, Vol 97, 649-657, Copyright © 1990 by Company of Biologists
Submitted on June 11, 1990
Accepted on September 26, 1990
1 Department of Biology, York University, 4700 Keele St, North York, Ontario, Canada M3J 1P3
We reported previously that Ca2+ deprivation of Dictyostelium discoideum amoebae inhibits both the induction by cyclic AMP of soluble cyclic nucleotide phosphodiesterase (PD) activity in wild-type cells and the constitutive production of this activity in mutant HC35 cells. In this study, the mutant strain has been used to characterize this phenomenon further and to attempt to identify the Ca2+-dependent step(s) in PD production. Incubation of HC35 cells with 0.9 mM EGTA increased the rate of 45Ca2+ efflux from preloaded cells and partially inhibited PD production. The effect of EGTA on both processes was enhanced considerably by the presence of 1 ftM A23187. This concentration of ionophore alone had little effect on either Ca2+ efflux or PD production. Addition of 1µM free extracellular Ca2+ to amoebae incubated with EGTA and A23187 increased PD production two- to sixfold. Ca2+ depletion did not appreciably inhibit total protein synthesis or total protein glycosylation as determined by the incorporation of [3H]leucine or [3H]mannose, respectively. Also, the abundance of PD mRNAs was approximately the same in Ca2+-depleted and control cells. In contrast, immunoblot analysis of extracellular fluids and intracellular extracts of these cells revealed a dramatic reduction (up to 85%) in the levels of PD-related polypeptides associated with the Ca2+-depleted cells. These results suggest that Ca2+ deprivation selectively inhibits PD production by impairing a post-transcriptional process.
Key words: cyclic nucleotide phosphodiesterase synthesis, inhibition by EGTA and A23187, Dictyostelium
Submitted on June 11, 1990
Accepted on September 26, 1990
This article has been cited by other articles:
|
|
 |
|
  B. Coukell, Y. Li, J. Moniakis, and A. Cameron The Ca2+/Calcineurin-Regulated cup Gene Family in Dictyostelium discoideum and Its Possible Involvement in Development Eukaryot. Cell, February 1, 2004; 3(1): 61 - 71. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J Moniakis, M. Coukell, and A Janiec Involvement of the Ca2+-ATPase PAT1 and the contractile vacuole in calcium regulation in Dictyostelium discoideum J. Cell Sci., January 2, 1999; 112(3): 405 - 414. [Abstract] [PDF]
|
|
|
|
|
|
Y Xie, M. Coukell, and Z Gombos Antisense RNA inhibition of the putative vacuolar H(+)-ATPase proteolipid of Dictyostelium reduces intracellular Ca2+ transport and cell viability J. Cell Sci., January 2, 1996; 109(2): 489 - 497. [Abstract] [PDF]
|
|
|
|
 |
|
 J. Moniakis, M. B. Coukell, and A. Forer Molecular Cloning of an Intracellular P-type ATPase from Dictyostelium That Is Up-regulated in Calcium-adapted Cells J. Biol. Chem., November 24, 1995; 270(47): 28276 - 28281. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. B. Coukell, A. M. Cameron, and N. R. Adames Involvement of intracellular calcium in protein secretion in Dictyostelium discoideum J. Cell Sci., October 1, 1992; 103(2): 371 - 380. [Abstract] [PDF]
|
|
