JCB logo
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text (PDF, 978K)
Right arrow Alert me when this article is cited
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 Meldolesi, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Meldolesi, J.
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 Journal of Cell Biology, Vol 61, 1-13, Copyright © 1974 by Rockefeller University Press

ARTICLE

DYNAMICS OF CYTOPLASMIC MEMBRANES IN GUINEA PIG PANCREATIC ACINAR CELLS

: I. Synthesis and Turnover of Membrane Proteins



J. Meldolesi 1

1 From the Department of Pharmacology, University of Milan, and the Center of Cytopharmacology of the Consiglio Nazionale delle Ricerche, 20192 Milan, Italy

The rate of synthesis and the turnover of cytoplasmic membrane proteins were determined in the acinar cells of guinea pig pancreas with the aim of investigating the mechanisms by which the intracellular transport of secretion products occurs. These cells are highly specialized toward protein secretion.

By means of in vitro pulse-chase experiments and in vivo double-labeling experiments, using radioactive L-leucine as the tracer, it was found that the turnover of secretory proteins is much faster than that of all membranes involved in their transport (rough and smooth microsome and zymogen granule membranes). Sodium dodecyl sulfate-polyacrylamide disk gel electrophoresis of membrane proteins revealed that in each of these membranes there is a marked heterogeneity of turnover; generally the high molecular weight polypeptides have a shorter half-life than the low molecular weight polypeptides.

These data indicate that the membranes participating in the intracellular transport of secretory proteins are not synthesized concomitantly with the latter. Rather, they are probably reutilized in several successive secretory cycles.

The possible relevance of these findings to other secretory systems is discussed.

Submitted on June 13, 1973
Revised on October 23, 1973


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