Am J Physiol Cell Physiol Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 266: C81-C94, 1994;
0363-6143/94 $5.00
This Article
Right arrow Full Text (PDF)
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 Van Dyke, R. W.
Right arrow Articles by Belcher, J. D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Van Dyke, R. W.
Right arrow Articles by Belcher, J. D.

AJP - Cell Physiology, Vol 266, Issue 1 C81-C94, Copyright © 1994 by American Physiological Society

ARTICLES

Acidification of three types of liver endocytic vesicles: similarities and differences

R. W. Van Dyke and J. D. Belcher
Department of Medicine, University of California School of Medicine, San Francisco 94143.

Endocytosed ligands move through a series of progressively more acidic vesicles. These differences in pH (pHi) could reflect differences in ion transport mechanisms. Vesicles representing three stages of endocytosis, compartment for uncoupling of receptor and ligand (CURL), multivesicular bodies (MVB), and receptor recycling compartment (RRC), were studied, and all exhibited ATP-dependent electrogenic acidification that was a saturable function of medium chloride. Initial rates of acidification differed (RRC > CURL > MVB), and proton influx was similar for CURL and RRC but slower for MVB. Steady-state ATP-dependent pHi in the three vesicles was more similar. Vesicle membrane potential was substantial (+41 to +69 mV) in low-chloride medium and greatest for RRC but was low (-6 to +6 mV) in 140 mM KCl. These vesicles also exhibited -22 to -37 mV Donnan potentials. Steady-state pump-generated proton electrochemical gradients (delta mu H+) ranged from 114 to 175 mV and were greater for CURL and RRC than for MVB; however, delta mu H+ changed little over a 140-fold difference in chloride concentration. Proton leak rates were faster in CURL and RRC than in MVB, but proton efflux was similar. Finally, proton fluxes and permeabilities, calculated with regard to surface area, differed in the opposite direction (MVB > CURL > RRC). Thus, for the endocytic vesicles studied, intrinsic differences in proton flux and in vesicle geometry could be demonstrated that contributed to differences in pre-steady-state vesicle pHi.


This article has been cited by other articles:


Home page
 J. Exp. Biol.Home page
J. A. Covi and S. C. Hand
V-ATPase expression during development of Artemia franciscana embryos: potential role for proton gradients in anoxia signaling
J. Exp. Biol., July 15, 2005; 208(14): 2783 - 2798.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
G. Chandy, M. Grabe, H.-P. H. Moore, and T. E. Machen
Proton leak and CFTR in regulation of Golgi pH in respiratory epithelial cells
Am J Physiol Cell Physiol, September 1, 2001; 281(3): C908 - C921.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. Rev.Home page
N. A. BRADBURY
Intracellular CFTR: Localization and Function
Physiol Rev, January 1, 1999; 79(1): 175 - 191.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online