Molecular and functional studies of membrane ion transporters

• Grant number: 04/01683-5
• Support Opportunities: Research Projects - Thematic Grants
• Duration: December 01, 2004 - September 30, 2009
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Gerhard Malnic
• Grantee: Gerhard Malnic
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Pesquisadores principais: Antonio Carlos Cassola ; Margarida de Mello Aires ; Nancy Amaral Reboucas
• Associated grant(s): 06/56710-2 - Down regulation of na/h exchanger nhe3 by dipeptidyl peptidase iv inhibitors: an in vivo study., AR.EXT

Abstract

The general object of this project is the investigation of the molecular and functional mechanisms of ion transport in cells, particularly of the epithelial type, originating from renal and other tissues. Among the methods that will be used for this purpose are renal micropuncture and microperfusion, molecular biology including transfection of wild type and mutant transporters into cultured cells, electrophysiology ("patch-clamp") for the analysis of individual ion channels, determination of cell volume regulation and the role of ion transporters in this regulation, measurement of cell ion activities by fluorescence microscopy allowing for the determination of cell pH and calcium levels. These studies will be performed in mammalian kidney, intestine, colon crypts, cells in primary and permanent cultures such as MDCK, T84, IRPTC and others. Transporters of H+, HCO3- and K+ will be investigated, including Na+/H+ exchangers, H+ and H+/K+ ATPases, K+ channels, Cl- /HCO3- exchangers, and Na+/HCO3- cotransporters, passive mechanisms, and the role of hormones (aldosterone, angiotensin, vasopressin, atrial natriuretic factor, parathyroid hormone) in the regulation of these mechanisms will be studied. Techniques for the determination of transepithelial and transmembrane (apical and basolateral) ion fluxes using microelectrodes or cell fluorescence will be used. Molecular properties of transporters such as the isoforms of the Na+/H+ exchanger and of protein kinase C, their genetic modulation and the role of protein regulators (NHERF) in the regulation of the transfer of H+ will be investigated. Cell signaling of the regulation of H+ and K+ ion transport will be studied in different experimental conditions. (AU)

Scientific publications

(4)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

CARRARO-LACROIX, LUCIENE R.; MALNIC, GERHARD; GIRARDI, ADRIANA C. C.. Regulation of Na+/H+ exchanger NHE3 by glucagon-like peptide 1 receptor agonist exendin-4 in renal proximal tubule cells. AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY, v. 297, n. 6, p. F1647-F1655, DEC 2009. (04/01683-5)

L.R. CARRARO-LACROIX; L.M.A. LESSA; R. FERNANDEZ; G. MALNIC. Physiological implications of the regulation of vacuolar H+-ATPase by chloride ions. Brazilian Journal of Medical and Biological Research, v. 42, n. 2, p. 155-163, 2009-02-00. (04/01683-5)

GIRARDI, ADRIANA CASTELLO COSTA; FUKUDA, LÍVIA EMY; ROSSONI, LUCIANA VENTURINI; MALNIC, GERHARD; REBOUÇAS, NANCY AMARAL. Dipeptidyl peptidase IV inhibition downregulates Na+-H+ exchanger NHE3 in rat renal proximal tubule. American Journal of Physiology : Renal Physiology, v. 294, n. 2, p. F414-F422, Feb. 2008. (04/01683-5)

CARRARO-LACROIX, LUCIENE R.; LESSA, LUCILIA M. A.; BEZERRA, CAMILA N. A.; PESSOA, THAISSA D.; SOUZA-MENEZES, JACKSON; MORALES, MARCELO M.; GIRARDI, ADRIANA C. C.; MALNIC, GERHARD. Role of CFTR and ClC-5 in Modulating Vacuolar H+-ATPase Activity in Kidney Proximal Tubule. CELLULAR PHYSIOLOGY AND BIOCHEMISTRY, v. 26, n. 4-5, p. 563-576, 2010. (04/01683-5)