The local generation of distinct phosphatidylinositol (PI) lipid species has been implicated in the regulation of numerous membrane trafficking events and in the control of cytoskeletal dynamics. The compartmentalized synthesis of noninterchangeable pools of PIs by PI-metabolizing enzymes is critical to the cell's ability to control these multiple PI-dependent functions independently. We are interested in the role of phosphatidylinositol kinases and inositol polyphosphate phosphatases in polarized membrane traffic in renal epithelial cells, and have found that apical and basolateral biosynthetic pathways are differentially sensitive to overexpression of the PI metabolizing enzymes PI-4 kinase beta and PI-5 kinase alpha. Moreover, the observation that Lowe Syndrome (a disease with severe renal manifestations) is caused by molecular defects in a Golgi-tocalized PI-catabolizing enzyme suggests a role for inositol polyphosphate 5-phosphatase activity in biosynthetic transport. In this proposal, we will correlate the effects of expressing individual PI-metabolizing enzymes on transport with actual changes in PI lipid composition across the Golgi complex and test hypotheses to explain the mechanisms by which distinct PI species regulate membrane traffic. These experiments will significantly enhance our understanding of how localized PI synthesis operates at a molecular level to regulate polarized biosynthetic traffic in normal and disease states. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK064613-01A1
Application #
6823889
Study Section
Cellular and Molecular Biology of the Kidney Study Section (CMBK)
Program Officer
Mullins, Christopher V
Project Start
2004-07-15
Project End
2008-06-30
Budget Start
2004-07-15
Budget End
2005-06-30
Support Year
1
Fiscal Year
2004
Total Cost
$325,908
Indirect Cost
Name
University of Pittsburgh
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Szalinski, Christina M; Guerriero, Christopher J; Ruiz, Wily G et al. (2013) PIP5KI? selectively modulates apical endocytosis in polarized renal epithelial cells. PLoS One 8:e53790
Rbaibi, Youssef; Cui, Shanshan; Mo, Di et al. (2012) OCRL1 modulates cilia length in renal epithelial cells. Traffic 13:1295-305
Welling, Paul A; Weisz, Ora A (2010) Sorting it out in endosomes: an emerging concept in renal epithelial cell transport regulation. Physiology (Bethesda) 25:280-92
Cui, Shanshan; Guerriero, Christopher J; Szalinski, Christina M et al. (2010) OCRL1 function in renal epithelial membrane traffic. Am J Physiol Renal Physiol 298:F335-45
Weisz, Ora A; Rodriguez-Boulan, Enrique (2009) Apical trafficking in epithelial cells: signals, clusters and motors. J Cell Sci 122:4253-66
Fölsch, Heike; Mattila, Polly E; Weisz, Ora A (2009) Taking the scenic route: biosynthetic traffic to the plasma membrane in polarized epithelial cells. Traffic 10:972-81
Butterworth, Michael B; Weisz, Ora A; Johnson, John P (2008) Some assembly required: putting the epithelial sodium channel together. J Biol Chem 283:35305-9
Weixel, Kelly M; Edinger, Robert S; Kester, Lauren et al. (2007) Phosphatidylinositol 4-phosphate 5-kinase reduces cell surface expression of the epithelial sodium channel (ENaC) in cultured collecting duct cells. J Biol Chem 282:36534-42
Guerriero, Christopher J; Weisz, Ora A (2007) N-WASP inhibitor wiskostatin nonselectively perturbs membrane transport by decreasing cellular ATP levels. Am J Physiol Cell Physiol 292:C1562-6

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