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Expression of myosin VI within the early endocytic pathway in adult and developing proximal tubules
- Source :
- American Journal of Physiology-Renal Physiology. 282:F785-F794
- Publication Year :
- 2002
- Publisher :
- American Physiological Society, 2002.
-
Abstract
- Myosin VI is a reverse-direction molecular motor implicated in membrane transport events. Because myosin VI is most highly expressed in the kidney, we investigated its renal localization by using high-resolution immunocytochemical and biochemical methods. Indirect immunofluorescence microscopy revealed myosin VI at the base of the brush border in proximal tubule cells. Horseradish peroxidase uptake studies, which labeled endosomes, and double staining for clathrin adapter protein-2 showed that myosin VI was closely associated with the intermicrovillar (IMV) coated-pit region of the brush border. Localization of myosin VI to the IMV region was confirmed at the electron microscopic level by colloidal gold labeling of ultrathin cryosections. In addition, antigen retrieval demonstrated a small but significant pool of myosin VI on the microvilli. To confirm the association of myosin VI with the IMV compartment, these membranes were separated from other membrane compartments by using 15–25% OptiPrep density gradients. Immunoblotting of the gradient fractions confirmed that myosin VI was enriched with markers for the IMV microdomain of the brush border, suggesting that myosin VI associates with proteins in this compartment. Finally, we examined the expression of myosin VI during nephron development. We found myosin VI present in a diffuse cytoplasmic pattern at stage II (S-shaped body phase) and that it was only redistributed fully to the brush border in the stage IV nephron. These studies support a model for myosin VI function in the endocytic process of the proximal tubule.
- Subjects :
- Physiology
Immunoblotting
Endocytic cycle
Fluorescent Antibody Technique
Endosomes
macromolecular substances
Biology
Endocytosis
Clathrin
Kidney Tubules, Proximal
Rats, Sprague-Dawley
Myosin
Centrifugation, Density Gradient
Molecular motor
medicine
Animals
Microscopy, Immunoelectron
Horseradish Peroxidase
Kidney
Microscopy, Confocal
Microvilli
Myosin Heavy Chains
Membrane transport
Rats
Cell biology
medicine.anatomical_structure
Animals, Newborn
Biochemistry
Renal physiology
biology.protein
Subjects
Details
- ISSN :
- 15221466 and 1931857X
- Volume :
- 282
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Renal Physiology
- Accession number :
- edsair.doi.dedup.....c6d74002f1a888ef99fcf902c334c713
- Full Text :
- https://doi.org/10.1152/ajprenal.00287.2001