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Identification of GTP-binding proteins in turtle urinary bladder epithelial cells
G M Dolson1, C Ribeiro, G Ulate
1Department of Medicine, Baylor College of Medicine, Houston, Tex.
Mineral and Electrolyte Metabolism
|January 1, 1994
Summary
This study identifies inhibitory (Gi) and stimulatory (Gs) G-proteins in turtle urinary bladder cells, crucial for regulating water and electrolyte transport, similar to mammalian systems.
Area of Science:
- Cellular biology
- Physiology
- Biochemistry
Background:
- Water and electrolyte transport in turtle urinary bladders mirrors mammalian collecting tubules.
- The roles of inhibitory (Gi) and stimulatory (Gs) G-proteins in this process are not fully understood.
Purpose of the Study:
- To identify and characterize Gi and Gs proteins in turtle urinary bladder epithelial cells.
- To investigate the presence and heterogeneity of these G-proteins in specific cell types.
Main Methods:
- Isolation of mucosal cells using Ficoll density gradients.
- Identification of Gi and Gs proteins via [32P] ADP ribosylation with pertussis and cholera toxins.
- Analysis using polyacrylamide gel electrophoresis and autoradiography.
Main Results:
- Gi and Gs proteins were identified in both carbonic anhydrase-rich and granular cells.
- Gi showed a heterogeneous doublet form, while Gs appeared as a single polypeptide.
- A unique 45-kD peptide was detected in granular cells and carbonic anhydrase-rich cells.
Conclusions:
- This research successfully identified and characterized Gi and Gs proteins in turtle urinary bladder epithelial cells.
- The findings provide insights into the molecular mechanisms of ion transport regulation in this model system.