Aquaglyceroporins: ancient channels for metalloids.
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ABSTRACT:
SUBMITTER: Bhattacharjee H
PROVIDER: S-EPMC2776386 | biostudies-literature | 2008 Nov
REPOSITORIES: biostudies-literature
Publications
Aquaglyceroporins: ancient channels for metalloids.
Bhattacharjee Hiranmoy H Mukhopadhyay Rita R Thiyagarajan Saravanamuthu S Rosen Barry P BP
Journal of biology 20081107 9
The identification of aquaglyceroporins as uptake channels for arsenic and antimony shows how these toxic elements can enter the food chain, and suggests that food plants could be genetically modified to exclude arsenic while still accumulating boron and silicon. ...[more]
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Project description:BackgroundAquaporins (AQPs), members of a superfamily of transmembrane channel proteins, are ubiquitous in all domains of life. They fall into a number of branches that can be functionally categorized into two major sub-groups: i) orthodox aquaporins, which are water-specific channels, and ii) aquaglyceroporins, which allow the transport of water, non-polar solutes, such as urea or glycerol, the reactive oxygen species hydrogen peroxide, and gases such as ammonia, carbon dioxide and nitric oxide and, as described in this review, metalloids.Scope of reviewThis review summarizes the key findings that AQP channels conduct bidirectional movement of metalloids into and out of cells.Major conclusionsAs(OH)3 and Sb(OH)3 behave as inorganic molecular mimics of glycerol, a property that allows their passage through AQP channels. Plant AQPs also allow the passage of boron and silicon as their hydroxyacids, boric acid (B(OH)3) and orthosilicic acid (Si(OH)4), respectively. Genetic analysis suggests that germanic acid (GeO2) is also a substrate. While As(III), Sb(III) and Ge(IV) are toxic metalloids, borate (B(III)) and silicate (Si(IV)) are essential elements in higher plants.General significanceThe uptake of environmental metalloids by aquaporins provides an understanding of (i) how toxic elements such as arsenic enter the food chain; (ii) the delivery of arsenic and antimony containing drugs in the treatment of certain forms of leukemia and chemotherapy of diseases caused by pathogenic protozoa; and (iii) the possibility that food plants such as rice could be made safer by genetically modifying them to exclude arsenic while still accumulating boron and silicon. This article is part of a Special Issue entitled Aquaporins.
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