The Na, K and H, K-ATPases are members of the P-type family of ion pumps and play critical roles in maintaining cellular homeostasis and transepithelial transport. The Na, K-ATPase creates ion gradients that maintain cellular osmotic balance and membrane potential. These gradients are exploited by transporting epithelia to drive the import and export of a wide range of solutes against steep concentration gradients. The H, K-ATPase is responsible for gastric acid secretion and also appears to play a role in renal potassium reabsorption. To carry out these functions, these pumps must be restricted to specific domains of the plasma membranes of polarized epithelial cells. The Na, K-ATPase resides at the basolateral surfaces of most polarized epithelial cell types. In the acid secreting parietal cells of the stomach the H, K-ATPase is stored in an intracellular vesicular compartment that fuses with apical plasma membrane in response to secretagogue stimulation. The activities of these ion pumps are tightly controlled through a variety of processes that regulate both their subcellular trafficking and their catalytic properties. In order to attain their appropriate subcellular distributions and to participate in their respective regulatory pathways, both pumps are likely to interact with a large number of accessory proteins. During the previous funding period we have identified a several novel partner polypeptides that appear to interact with these pumps to modulate their cell biologic and functional properties. We find that the Na,K-ATPase associates with both neurabin II/spinophilin and arrestin, suggesting that the sodium pump may be susceptible to regulatory mechanisms similar to those that govern G protein coupled receptor signaling. In addition, the Na, K and H, K-ATPase each form complexes with a member of the tetraspan family of transmembrane interacting proteins, and these associations profoundly influence pump trafficking. In the present proposal we will carry out studies designed to 1) determine the molecular and cell biologic mechanisms through which neurabin II/spinophilin and arrestin modulate the function of the Na, KATPase, 2) characterize the physiologic effects of interactions between ion pumps and tetraspans, and 3) examine the role of interacting proteins in governing ion pump function in vivo. These studies will allow us to define the physiological significance of these novel interactions, and to understand their involvement in governing pump function both under normal circumstances and in the context of pathological conditions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK072614-19
Application #
7455890
Study Section
Special Emphasis Panel (ZRG1-RUS-D (02))
Program Officer
Ketchum, Christian J
Project Start
1989-07-01
Project End
2009-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
19
Fiscal Year
2008
Total Cost
$410,482
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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