Development of polarized plasma membrane domains is a prerequisite for renal epithelial function and its perturbation contributes to a variey of pathologies. Thus, elucidating the mechanisms through which polarity is generated and maintained is fundamental to developing a thorough understanding of renal physiology. Epithelial cells avail themselves of a complex sorting apparatus to create and maintain the compositional integrity of their plasma membrane domains. During the previous funding period of this award we have employed new approaches that have illuminated aspects of the sorting and signaling systems involved in generating and maintaining renal epithelial cell polarity. Our previous efforts focused in part upon the sorting and trafficking properties of the Na,K-ATPase, the basolateral ion pump that generates the driving force for the vast majority of renal fluid and electrolyte transport. A number of recent studies suggest that the Na,K-ATPase is not simply an occupant of the basolateral cell surface, but is in addition an active participant in the intercelllar communication and signaling pathways that establish the composition and structure of the basolateral plasma membrane domain. In the present application we propose to apply innovative tools to investigate further the pathways and partners involved in the sorting and delivery of apical and basolateral membrane proteins. We will carry out studies that explore novel hypotheses relating to both the cellular mechanisms responsible for epithelial polarity and to their physiological implications. Towards this end we will 1) Define pathways pursued by newly synthesized proteins as they travel to the apical and basolateral domains of the plasma membrane; 2) Determine how sorting and trafficking behaviors vary among renal epithelial cell types and during the course of renal development; and 3) Identify and characterize temporal and polarity-dependent interactomes. Through this work we will develop new insights into the mechanisms that mediate membrane protein trafficking in renal epithelial cells and that therefore determine the physiological properties of the renal tubule.

Public Health Relevance

Kidney cells carry out ion transport that is responsible for determining the body's salt and water composition. To fulfil this responsibility, kidney cells need to be polarized, meaning that their surface domains must be divided into two subdomains that possess different protein compositions that determine their functional characteristics. Developing insight into the mechanisms that generate and maintain this polarity is a critical prerequisite to understanding the physiology of the kidney.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK072614-27
Application #
9307800
Study Section
Kidney Molecular Biology and Genitourinary Organ Development (KMBD)
Program Officer
Ketchum, Christian J
Project Start
1989-07-01
Project End
2019-06-30
Budget Start
2017-07-01
Budget End
2018-06-30
Support Year
27
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Yale University
Department
Physiology
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Gilder, Allison L; Chapin, Hannah C; Padovano, Valeria et al. (2018) Newly synthesized polycystin-1 takes different trafficking pathways to the apical and ciliary membranes. Traffic 19:933-945
Matlin, Karl S; Caplan, Michael J (2017) The secretory pathway at 50: a golden anniversary for some momentous grains of silver. Mol Biol Cell 28:229-232
Padovano, Valeria; Kuo, Ivana Y; Stavola, Lindsey K et al. (2017) The polycystins are modulated by cellular oxygen-sensing pathways and regulate mitochondrial function. Mol Biol Cell 28:261-269
Stoops, Emily H; Hull, Michael; Caplan, Michael J (2016) Newly synthesized and recycling pools of the apical protein gp135 do not occupy the same compartments. Traffic 17:1272-1285
Farr, Glen A; Hull, Michael; Stoops, Emily H et al. (2015) Dual pulse-chase microscopy reveals early divergence in the biosynthetic trafficking of the Na,K-ATPase and E-cadherin. Mol Biol Cell 26:4401-11
Hatano, Ryo; Akiyama, Kaori; Tamura, Atsushi et al. (2015) Knockdown of ezrin causes intrahepatic cholestasis by the dysregulation of bile fluidity in the bile duct epithelium in mice. Hepatology 61:1660-71
Stoops, Emily H; Hull, Michael; Olesen, Christina et al. (2015) The periciliary ring in polarized epithelial cells is a hot spot for delivery of the apical protein gp135. J Cell Biol 211:287-94
Alves, Daiane S; Thulin, Gunilla; Loffing, Johannes et al. (2015) Akt Substrate of 160 kD Regulates Na+,K+-ATPase Trafficking in Response to Energy Depletion and Renal Ischemia. J Am Soc Nephrol 26:2765-76
Stoops, Emily H; Caplan, Michael J (2014) Trafficking to the apical and basolateral membranes in polarized epithelial cells. J Am Soc Nephrol 25:1375-86
Jouret, François; Wu, Jingshing; Hull, Michael et al. (2013) Activation of the Ca²+-sensing receptor induces deposition of tight junction components to the epithelial cell plasma membrane. J Cell Sci 126:5132-42

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