Biochemical pathways of arsenic uptake from the environment to human cells

Arsenic is one of the most toxic elements on Earth and causal factor of serious poisonings and diseases. Agency for Toxic Substance and Disease Registry placed this metaloid on the 1st place of Substance Priority List. The explanation of mechanisms of As migration from environment to organisms is crucial step on a way to limit poisonings caused by this element. This review presents the most actual knowledge about As transporters involved in migration and distribution of As from the environment via food chain into human body, focusing on molecular cell transporters of arsenic. The mechanism of translocation depends on the As form. Three allotropes and nine states of oxidation either organic As (Asorg) and inorganic As (Asin) were identified. In biochemical aspect the most significant are As(III) and As(V) forms. Pit and Pst are transporters responsible for As(V) intake in every organism regarding As(V) form similarity to phosphate compounds. In plants, e.g. domesticated Oryza sativa different specialized transmembrane PHT proteins like OsPht1;1 and OsPht1;8 and their homologues uptake and distribute As(V) compounds within plant. Asin(III) migration pathway leads via aquaglyceroporins such like GlpF in E. coli, NIPs members (e.g. AtNip, OsNip, OsPIP) in plants or AQPs in mammalian cells. In dependence on type of organism aquaglyceroporins are transporters involved in uptake as well as efflux of As(III) from the cell. Therefore, organisms can contribute to increase of more toxic As form in environment. Another pathways for As(III) uptake are hexose permeases identified in yeast and mammalian cells. Organic arsenic compounds intake was studied mainly on As methylated derivatives and it was shown that is processed via aquaglyceroporins like Asin(III) forms, although molecular mechanism of Asorg(III) and Asorg(V) seems to be different. Correspondence to: Dariusz Latowski, Department of Plant Physiology and Biochemistry, Faculty of Biotechnology, Biochemistry and Biophysics, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland, Tel: (+48) 12 664 60 02; Fax: (+48) 12 664 69 02; E-mail: [email protected]