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Proceedings Paper

Intracellular pH (pHin) and cytosolic calcium ([Ca2+]cyt) regulation via ATPases: studies in cell populations, single cells, and subcellular compartments
Author(s): Jose D. Rojas; Shankar C. Sanka; Sandor Gyorke; Donald E. Wesson; Akwasi Minta; Raul Martinez-Zaguilan
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Paper Abstract

Changes in pHin and (Ca2+)cyt are important in the signal transduction mechanisms leading to many physiological responses including cell growth, motility, secretion/exocytosis, etc. The concentrations of these ions are regulated via primary and secondary ion transporting mechanisms. In diabetes, specific pH and Ca2+ regulatory mechanism might be altered. To study these ions, we employ fluorescence spectroscopy, and cell imagin spectroscopy/confocal microscopy. pH and Ca2+ indicators are loaded in the cytosol with acetoxymethyl ester forms of dyes, and in endosomal/lysosomal (E/L) compartments by overnight incubation of cells with dextran- conjugated ion fluorescent probes. We focus on specific pH and Ca2+ regulatory systems: plasmalemmal vacuolar- type H+-ATPases (pm V-ATPases) and sarcoplasmic/endoplasmic reticulum Ca2+-ATPases (SERCA). As experimental models, we employ vascular smooth muscle (VSM) and microvascular endothelial cells. We have chosen these cells because they are important in blood flow regulation and in angiogenesis. These processes are altered in diabetes. In many cell types, ion transport processes are dependent on metabolism of glucose for maximal activity. Our main findings are: (a) glycolysis coupling the activity of SERCA is required for cytosolic Ca2+ homeostasis in both VSM and microvascular endothelial cells; (b) E/L compartments are important for pH and Ca2+ regulation via H+-ATPases and SERCA, respectively; and (c) pm-V- ATPases are important for pHin regulation in microvascular endothelial cells.

Paper Details

Date Published: 2 July 1999
PDF: 13 pages
Proc. SPIE 3600, Biomedical Imaging: Reporters, Dyes, and Instrumentation, (2 July 1999); doi: 10.1117/12.351011
Show Author Affiliations
Jose D. Rojas, Texas Tech Univ. Health Sciences Ctr. (United States)
Shankar C. Sanka, Texas Tech Univ. Health Sciences Ctr. (United States)
Sandor Gyorke, Texas Tech Univ. Health Sciences Ctr. (United States)
Donald E. Wesson, Texas Tech Univ. Health Sciences Ctr. (United States)
Akwasi Minta, Texas Fluorescence Labs. (United States)
Raul Martinez-Zaguilan, Texas Tech Univ. Health Sciences Ctr. (United States)

Published in SPIE Proceedings Vol. 3600:
Biomedical Imaging: Reporters, Dyes, and Instrumentation
Eva Marie Sevick-Muraca; Darryl J. Bornhop; Christopher H. Contag; Eva Marie Sevick-Muraca, Editor(s)

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