JCB logo
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article
Right arrow Full Text
Right arrow Full Text (PDF, 447K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by He, H.
Right arrow Articles by Distelhorst, C. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by He, H.
Right arrow Articles by Distelhorst, C. W.
Right arrowPubmed/NCBI databases
*Compound via MeSH
*Substance via MeSH
Hazardous Substances DB
*CALCIUM COMPOUNDS
*CALCIUM, ELEMENTAL
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/1997//1219 $5.00
The Journal of Cell Biology, Volume 138, Number 6, , 1997 1219-1228


Article

Maintenance of Calcium Homeostasis in the Endoplasmic Reticulum by Bcl-2



Huiling He, Minh Lam, Thomas S. McCormick, and Clark W. Distelhorst

Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106

The oncogene bcl-2 encodes a 26-kD protein localized to intracellular membranes, including the ER, mitochondria, and perinuclear membrane, but its mechanism of action is unknown. We have been investigating the hypothesis that Bcl-2 regulates the movement of calcium ions (Ca2+) through the ER membrane. Earlier findings in this laboratory indicated that Bcl-2 reduces Ca2+ efflux from the ER lumen in WEHI7.2 lymphoma cells treated with the Ca2+-ATPase inhibitor thapsigargin (TG) but does not prevent capacitative entry of extracellular calcium. In this report, we show that sustained elevation of cytosolic Ca2+ due to capacitative entry is not required for induction of apoptosis by TG, suggesting that ER calcium pool depletion may trigger apoptosis. Bcl-2 overexpression maintains Ca2+ uptake in the ER of TG-treated cells and prevents a TG-imposed delay in intralumenal processing of the endogenous glycoprotein cathepsin D. Also, Bcl-2 overexpression preserves the ER Ca2+ pool in untreated cells when extracellular Ca2+ is low. However, low extracellular Ca2+ reduces the antiapoptotic action of Bcl-2, suggesting that cytosolic Ca2+ elevation due to capacitative entry may be required for optimal ER pool filling and apoptosis inhibition by Bcl-2. In summary, the findings suggest that Bcl-2 maintains Ca2+ homeostasis within the ER, thereby inhibiting apoptosis induction by TG.


Address all correspondence to Clark W. Distelhorst, Department of Medicine, Biomedical Research Building Room 329, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106-4937. Tel.: (216) 368-1176. Fax: (216) 368-1166. e-mail: cwd{at}po.cwru.edu

1. Abbreviation used in this paper: TG, thapsigargin.



Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents