Main Research Topics of Epithelial Transport
- Amino acid transporters: Identification, functional characterization and elucidation of their role.
A long term goal of this project is to understand the mechanisms of transepithelial amino acid transport at the level of the individual transporters and of their cooperation in single and opposite membranes of epithelial cells.
Dysfunction of transport proteins involved in epithelial transport of aminoacids leads to the genetic diseases cystinuria, lysinuric protein intolerance and Hartnup disease.
- Elucidation of the cellular mechanisms leading to Na+ transport regulation by aldosterone.
Identification of early aldosterone regulated gene products in mouse distal nephron using Affymetrix chips and analysis of their potential role as mediators of Na+ channel and Na+ pump regulation.
Dysregulation of this transport affects blood pressure control such that its understanding could lead to the identification of genetic risk factors and thus to improved prevention and treatment of blood pressure disorders.
- Mechanisms of Sodium-Coupled Cotransport of Inorganic Phosphate and Neutral Amino Acids
The goal of Dr Ian Forster’s project is to elucidate the mechanism of Na+-coupled cotransport at the molecular level. He is investigating the transport kinetics and structure-function relationships of members of two representative solute carrier families that are found in epithelial tissue: inorganic phosphate (Pi) cotransporters (NaPi-IIa/b/c) from the SLC34 family and neutral amino acid transporters B0AT1 and B0AT3 (XT2) from the SLC6 family.
As both transporter families contain electrogenic isoforms, he will use electrophysiological techniques including voltage-clamp fluorometry to investigate their kinetics and structure-function relationships in real-time.
- Main experimental models:
Differentiated cultures of various cell lines (i.e. A6, MDCK, M1) to study transepithelial Na+
and amino acid transports. Expression of exogenous gene products in these cell lines and
in Xenopus oocytes.
Mouse physiology: Renal and intestinal transport, integrative animal physiology.
Use of electrophysiological techniques and flux measurements in intact and semi-intact
epithelia as well as in Xenopus oocytes.
Video imaging, transport measurements in ex vivo preparations.
cDNA cloning, characterization, expression in Xenopus oocytes or epithelial cell lines, assessment of tissue distribution/regulation of corresponding mRNAs.
Investigation of localization, regulation and interactions of transport proteins using various
labelling methods (surface, biosynthetic etc.) and antibody-related techniques (immunoprecipitation/Westernblot/immunocytochemistry).