Molecular and functional studies of ion transporters in membranes

• Grant number: 99/12866-3
• Support Opportunities: Research Projects - Thematic Grants
• Start date: October 01, 2000
• End date: November 30, 2004
• Field of knowledge: Biological Sciences - Biophysics - Cellular Biophysics
• 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

Abstract

The general objective 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

(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)

AMORIM, JOSÉ B. O.; MUSA-AZIZ, RAIF; MELLO-AIRES, MARGARIDA; MALNIC, GERHARD. Signaling path of the action of AVP on distal K+ secretion. Kidney International, v. 66, n. 2, p. 696-704, Aug. 2004. (99/12866-3)

CARRARO-LACROIX, LUCIENE REGINA; RAMIREZ, MARCO ANTONIO; ZORN, TELMA M. T.; REBOUÇAS, NANCY AMARAL; MALNIC, GERHARD. Increased NHE1 expression is associated with serum deprivation-induced differentiation in immortalized rat proximal tubule cells. American Journal of Physiology : Renal Physiology, v. 291, n. 1, p. F129-F139, 2006. (99/12866-3)