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Plasticity of functional epithelial polarity
Nature
|November 4, 1985
Summary
Kidney epithelial cell polarity, crucial for transport, can be reversed by environmental changes. This study demonstrates that acid-loading can switch bicarbonate-secreting cells to a proton-secreting phenotype.
Area of Science:
- Cell Biology
- Physiology
- Renal Physiology
Background:
- Epithelial cells exhibit polarity, with distinct apical and basolateral membrane proteins and transport functions.
- This asymmetry is typically considered fixed after terminal differentiation.
- Vectorial transport relies on differential protein sorting and polarized endocytosis/exocytosis.
Purpose of the Study:
- To investigate the plasticity of epithelial cell polarity in response to environmental stimuli.
- To determine if transepithelial transport polarity can be reversed.
- To characterize the functional polarity of specific kidney tubule cells.
Main Methods:
- Analysis of transport protein localization and function in kidney epithelial cells.
- Induction of experimental acid-loading in animals.
- Functional characterization of bicarbonate-secreting and proton-secreting cells.
Main Results:
- Transepithelial H+ transport, endocytosis, and exocytosis polarity can be reversed by environmental stimuli.
- Bicarbonate-secreting cells in the cortical collecting tubule possess apical Cl-/HCO3- exchangers and basolateral proton pumps.
- Acid-loading induced a functional polarity switch in bicarbonate-secreting cells, mimicking proton-secreting cells.
Conclusions:
- Epithelial cell polarity is not always invariant and can be dynamically regulated.
- Environmental cues, such as acid-loading, can alter the functional phenotype of kidney epithelial cells.
- This plasticity has significant implications for understanding renal acid-base homeostasis and disease.