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This Article Full Text Full Text (PDF) All Versions of this Article: 93/3/303    most recent expphysiol.2007.037523v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Boyd, C. A. R. Search for Related Content PubMed PubMed Citation Articles by Boyd, C. A. R. Related Collections Lectures

¹ Department of Physiology, Anatomy & Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford OX1 3QX, UK

Abstract

The hallmark of epithelial cells is their functional polarization. It is those membrane proteins that are distributed differentially, either to the apical or to the basal surface, that determine epithelial physiology. Such proteins will include ‘pumps’, ‘channels’ and ‘carriers’, and it is the functional interplay between the actions of these molecules that allows the specific properties of the epithelium to emerge. Epithelial properties will additionally depend on: (a) the extent to which there may be a route between adjacent cells (the ‘paracellular’ route); and (b) the folding of the epithelium (as, for example, in the loop of Henle). As for other transporters, there is polarized distribution of amino-acid carriers; the molecular basis of these is of considerable current interest with regard to function, including ‘inborn errors’ (amino-acidurias); some of these transporters have additional functions, such as in the regulation of cell fusion, in modulating cell adherence and in activating intracellular signalling pathways. Collaboration of physiologists with fly geneticists has generated new insights into epithelial function. One example is the finding that certain amino-acid transporters may act as ‘transceptors’ and play a role as sensors of the extracellular environment that then regulate intracellular pathways controlling cell growth.

(Received 31 July 2007; accepted after revision 5 December 2007; first published online 20 December 2007)
Corresponding author C. A. R. Boyd: Department of Physiology, Anatomy & Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford OX1 3QX, UK. Email: richard.boyd{at}dpag.ox.ac.uk

In 2007 the G. L. Brown Prize Lecture was given by Professor C. A. R. Boyd at the Universities of Dundee, Belfast, London (St George's), Warwick, Liverpool, Cambridge and Oxford.