This proposal continues studies that combine physiological and ultrastructural analysis to understand membrane dynamics and its role in vasopressin (ADH) action. These studies of the toad urinary bladder will characterize important features of the intramembrane particle aggregates and their role in the water permeability response. Utilizing a new """"""""hyperstretch"""""""" procedure that flattens the apical membrane to allow a comprehensive evaluation of particle aggregate area, a rigorous evaluation of these structures will be carried out for conditions where previous studies indicate a dissociation between aggregates and water permeability response. These studies will also assess whether the aggregates associated with fused aggrephores and revealed by hyperstretch are important sites of water flow. Other studies will use the """"""""composite replica"""""""" methodology,k recently developed by this laboratory, to examine the cytoplasmic membrane surface in order to establish the relationship of cytoskeletal elements to the aggregates. Membrane retrieval into the endosomal system following ADH reversal will be studied to identify the site where aggregates and fluid phase markers are sorted. By covalently labeling components on the mucosal surface with biotin, the recycling of aggregate constituents will be evaluated. Antibodies to specific aggrephore components will be localized in control and ADH-stimulated bladders using a range of sensitive protocols including a new labeled composite replica strategy. This should make it possible to determine which protein(s) relate directly to the aggregates and are likely water channel components.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK032839-09
Application #
3231197
Study Section
Physiology Study Section (PHY)
Project Start
1984-03-01
Project End
1995-03-31
Budget Start
1992-04-01
Budget End
1993-03-31
Support Year
9
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Maryland Baltimore
Department
Type
Schools of Medicine
DUNS #
003255213
City
Baltimore
State
MD
Country
United States
Zip Code
21201
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Li, Lijun; Garikepati, R Mayuri; Tsukerman, Susanna et al. (2013) Reduced ENaC activity and blood pressure in mice with genetic knockout of the insulin receptor in the renal collecting duct. Am J Physiol Renal Physiol 304:F279-88
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Wade, James B (2011) Statins affect AQP2 traffic. Am J Physiol Renal Physiol 301:F308
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Fang, Liang; Garuti, Rita; Kim, Bo-Young et al. (2009) The ARH adaptor protein regulates endocytosis of the ROMK potassium secretory channel in mouse kidney. J Clin Invest 119:3278-89
Wang, Ying; O'Connell, Jeffrey R; McArdle, Patrick F et al. (2009) From the Cover: Whole-genome association study identifies STK39 as a hypertension susceptibility gene. Proc Natl Acad Sci U S A 106:226-31

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