pH Microdomains in Oligodendrocytes

Oligodendrocytes (OLs) are cells that produce myelin in the central nervous system. Here we use ratiometric pH indicator dye to analyze intracellular pH in OLs in culture. The results reveal alkaline microdomains, which predominate in the perikaryon and proximal dendrites, and acidic microdomains, w...

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Bibliographic Details
Published in:The Journal of biological chemistry 2004-08, Vol.279 (35), p.37115-37123
Main Authors: Ro, Hyun-ah, Carson, John H
Format: Article
Language:English
Subjects:
Animals
Biological Transport
Blotting, Western
Calibration
Cytoplasm - metabolism
Dendrites - metabolism
Hydrogen-Ion Concentration
Image Processing, Computer-Assisted
Membrane Microdomains - chemistry
Mice
Microscopy, Confocal
Microscopy, Fluorescence
Models, Biological
Oligodendroglia - metabolism
Photons
Precipitin Tests
Protein Structure, Tertiary
Rats
Sodium-Bicarbonate Symporters
Sodium-Hydrogen Exchangers - chemistry
Spectrometry, Fluorescence
Time Factors
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Summary:Oligodendrocytes (OLs) are cells that produce myelin in the central nervous system. Here we use ratiometric pH indicator dye to analyze intracellular pH in OLs in culture. The results reveal alkaline microdomains, which predominate in the perikaryon and proximal dendrites, and acidic microdomains, which predominate in distal dendrites. Spatial nonuniformity of pH is generated by differential subcellular distribution of Na + /H + exchanger (NHE), which is localized in a punctate distribution in the perikaryon and proximal processes, cotransporter (NBC), which is localized in a punctate distribution in distal dendrites, and carbonic anhydrase isotype II (CAII), which is colocalized with either NHE or NBC. Inhibition of NHE activity by amiloride inhibits regeneration of alkaline microdomains after cytoplasmic acidification, whereas the inhibition of CAII activity with ethoxyzolamide inhibits acidification of dendrites. Fluorescence correlation spectroscopy analysis of CAII microinjected into OLs reveals freely diffusing protein throughout the cell as well as protein associated predominantly with NHE in the perikaryon and predominantly with NBC in the dendrites. Alkaline and acidic microdomains could be generated by transport metabolons consisting of CAII associated with NHE or NBC, respectively. This study provides the first evidence for pH microdomains in cells and describes a mechanism for how they are generated.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M403099200