Award details

Membrane targeting of iron transporters induced by changes in dietary iron

Reference	BB/C502522/1
Principal Investigator / Supervisor	Professor Andrew McKie
Co-Investigators / Co-Supervisors	Dr Robert Simpson
Institution	King's College London
Department	Nutritional Sciences
Funding type	Research
Value (£)	208,268
Status	Completed
Type	Research Grant
Start date	01/10/2004
End date	30/09/2007
Duration	36 months

Abstract

The duodenal mucosa is the key site for regulating absorption of both forms of iron. Major advances have been made in understanding the mechanisms of dietary iron absorption in recent years and a number of key proteins have been identified. The key players are an apical divalent metal transporter (DMT1), an apical ferric reductase (Dcytb), a basolateral ferrous iron transporter (lreg1 or ferroportin) and a basolateral ferroxidase (Hephaestin). In addition we have recently identified a putative haem carrier protein (HCP1). While the identification of these proteins have advanced our knowledge of how iron is absorbed from the diet little is known about the regulation of these proteins. Preliminary data suggests that the sub cellular targeting of Dcytb DMT1 and HCP1 proteins within the duodenal enterocyte is regulated post-translationally by changes in the enterocyte iron concentrations. Since the enterocyte iron levels can be rapidly altered by the levels of dietary iron and/or haem this mechanism of regulation of iron transporters is likely to be important in ultimately determining how much iron is absorbed from the diet. The aim of this proposal will be to investigate the iron-regulated membrane targeting of intestinal iron transport proteins both in duodenal enterocytes and cultured cells and to identify the nature of the post-translational modification. We will use duodenal enterocytes as well as cultured cells to investigate this phenomenon. To investigate the phenomenon in vivo iron def mice will be used and given different intragastric doses of iron and haem and sub-cellular localisation of DMT1, Dcytb and HCP1 determined by immunocytochemistry. mRNA and protein levels will be determined in the same experiments. Changes in gel migration of the proteins by Western blot analysis may indicate post-translational modifications have taken place as a result of changes in dietary iron and/or haem. In addition to the effect of iron/haem on protein sub-cellular localisation in mature enterocytes we will also investigate the phenomenon in cultured cells. For these studies we will initially focus on HCP1 in Hela cells since we have an expression system in place, however this can be adapted to include Dcytb and DMT1 if required. Experiments will include metabolically labelling cells to determine whether phophorylation is involved in targeting proteins.

Summary

unavailable

Committee	Closed Committee - Agri-food (AF)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search