Intracellular pH (pHin) and cytosolic calcium ([Ca2+]cyt) regulation via ATPases: Studies in cell populations, single cells and subcellular compartments

Jose D. Rojas, Shankar Sanka, Sandor Gyorke, Donald E. Wesson, Akwasi Minta, Raul Martinez-Zaguilan

Research output: Contribution to journalConference article

3 Scopus citations

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 mechanisms might be altered. To study these ions, we employ fluorescence spectroscopy (cell populations attached to coverslips), and cell imaging spectroscopy/confocal microscopy (single cells and discrete subcellular compartments). 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 (pmV-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+ ([Ca2+]cyt) 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.

Original languageEnglish (US)
Pages (from-to)51-63
Number of pages13
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3600
StatePublished - Jan 1 1999
Externally publishedYes
EventProceedings of the 1999 Biomedical Imaging: Reporters, Dyes, and Instrumentation - San Jose, CA, USA
Duration: Jan 26 1999Jan 28 1999

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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