Phosphatase Subfamily Acr2

Phosphatase Classification: Superfamily Cys-based II (Rhodanese): Family CDC25: Subfamily Acr2

Acr2, phosphatase or arsenate reductase?

Acr2 is found in fungi, plants and protists, but not in animals. It is close to CDC25 in both sequence and structure. Yeast has both CDC25 and Acr2 orthologs (MIH1 and ARR2, respectively). They are generally regarded as tyrosine phosphatase involved in cell cycle and arsenate reductase, respectively. However, in plants, Acr2 is the only gene close to CDC25, and it is controversial whether it functions as both phosphatase and arsenate reductase in vivo, and if not, what its major function is (see below). Actually, it is not very surprising that Acr2s can complement the arsenate-sensitive phenotype of arsenate reductase deletion strain of E. coli or of Saccharomyces cerevisiae, since even human CDC25B and CDC25C has been shown to have arsenate reductase activity in vitro [1].

A brief of arsentate reductase

Prokaryotes and eukaryotes use arsenate reductases of distinct folds. E. coli uses ArsC, which belongs to Superfamily Cys-based III, the same as LMWPTP and SSU72. Eukaryotes, particularly fungi, plants and protists, may use ACR2 which have the same fold as CDC25 [2]. However, knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana and Saccharomyces cerevisiae , which implies the existence of other arsenate reductase(s) in plants and yeast [3].

Saccharomyces cerevisiae

Overexpressed in E. coli, ARR2, the ACR2 gene of Saccharomyces cerevisiae, was shown to exhibit arsenate reductase activity and complement the arsenate-sensitive phenotype of an ArsC deletion in E. coli [2, 4, 5]. The Cx5R motif is required for its catalytic activity as arsenate reductase [6]. Besides ARR2, yeast has MIH1 and YCH1 of CDC25 subfamily.

Arabidopsis thaliana

Acr2 of Arabidopsis thaliana was initially characterized as a phosphatase, given the evidences: i) protein structure solved by NMR [7], ii) recombinant expression in E. coli shows tyrosine phosphatase activity towards artificial substrate [8], and iii) overexpression in fission yeast function suggests it is a mitotic accelerator [9]. However, its overexpression or knock-out have no obvious cell cycle phenotype [10].

Arabidopsis thaliana Acr2 has been suggested to play a role in arsenate reduction [11, 12, 13]. However, knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana and Saccharomyces cerevisiae [3].

Oryza sativa (rice)

Rice has two Acr2s, which can complement the arsenate-sensitive phenotype of an ArsC deletion in E. coli at different levels[14]. The two genes not only reduce arsenate to arsenite in vitro, but also exhibit phosphatase activity. Mutagenesis of cysteine residues in the catalytic motif CX5R led to nearly complete loss of both phosphatase and arsenate reductase activities [14].

Pteris vittata (fern)

"Pteris vittata" has a single ACR2 (PvACR2). It product protein can suppress the arsenate sensitivity and arsenic hyperaccumulation phenotypes of yeast (Saccharomyces cerevisiae) lacking the arsenate reductase gene ACR2 [13, 15]. Interestingly, PvACR2 has replaced arginine with serine at the catalytic motif Cx5R, previously shown to be essential for phosphatase and reductase activity. While Acr2s in Arabidopsis thaliana and rice show both arsenate reductase and phosphatase activities, PvACR2 only shows arsenate reductase activity [15].

Chlamydomonas reinhardtii (green alga)

Chlamydomonas reinhardtii has two Acr2s. One of them complement the arsenate-sensitive phenotype of an ArsC deletion in E. coli [16].

Leishmania major

Leishmania major Acr2 was able to complement the arsenate-sensitive phenotype of an arsC deletion strain of E. coli or an ScACR2 deletion strain of Saccharomyces cerevisiae [17].

Reference

1. Bhattacharjee H, Sheng J, Ajees AA, Mukhopadhyay R, and Rosen BP. Adventitious arsenate reductase activity of the catalytic domain of the human Cdc25B and Cdc25C phosphatases. Biochemistry. 2010 Feb 2;49(4):802-9. DOI:10.1021/bi9019127 |
2. Yeo HK and Lee JY. Crystal structure of Saccharomyces cerevisiae Ygr203w, a homolog of single-domain rhodanese and Cdc25 phosphatase catalytic domain. Proteins. 2009 Aug 1;76(2):520-4. DOI:10.1002/prot.22420 |
3. Liu W, Schat H, Bliek M, Chen Y, McGrath SP, George G, Salt DE, and Zhao FJ. Knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana: implications for as detoxification and accumulation in plants. PLoS One. 2012;7(8):e42408. DOI:10.1371/journal.pone.0042408 |
4. Mukhopadhyay R and Rosen BP. Saccharomyces cerevisiae ACR2 gene encodes an arsenate reductase. FEMS Microbiol Lett. 1998 Nov 1;168(1):127-36. DOI:10.1111/j.1574-6968.1998.tb13265.x |
5. Mukhopadhyay R, Shi J, and Rosen BP. Purification and characterization of ACR2p, the Saccharomyces cerevisiae arsenate reductase. J Biol Chem. 2000 Jul 14;275(28):21149-57. DOI:10.1074/jbc.M910401199 |
6. Mukhopadhyay R and Rosen BP. The phosphatase C(X)5R motif is required for catalytic activity of the Saccharomyces cerevisiae Acr2p arsenate reductase. J Biol Chem. 2001 Sep 14;276(37):34738-42. DOI:10.1074/jbc.M103354200 |
7. Landrieu I, da Costa M, De Veylder L, Dewitte F, Vandepoele K, Hassan S, Wieruszeski JM, Corellou F, Faure JD, Van Montagu M, Inzé D, and Lippens G. A small CDC25 dual-specificity tyrosine-phosphatase isoform in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2004 Sep 7;101(36):13380-5. DOI:10.1073/pnas.0405248101 |
8. Landrieu I, da Costa M, De Veylder L, Dewitte F, Vandepoele K, Hassan S, Wieruszeski JM, Corellou F, Faure JD, Van Montagu M, Inzé D, and Lippens G. A small CDC25 dual-specificity tyrosine-phosphatase isoform in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2004 Sep 7;101(36):13380-5. DOI:10.1073/pnas.0405248101 |
9. Sorrell DA, Chrimes D, Dickinson JR, Rogers HJ, and Francis D. The Arabidopsis CDC25 induces a short cell length when overexpressed in fission yeast: evidence for cell cycle function. New Phytol. 2005 Feb;165(2):425-8. DOI:10.1111/j.1469-8137.2004.01288.x |
10. Boudolf V, Inzé D, and De Veylder L. What if higher plants lack a CDC25 phosphatase?. Trends Plant Sci. 2006 Oct;11(10):474-9. DOI:10.1016/j.tplants.2006.08.009 |
11. Bleeker PM, Hakvoort HW, Bliek M, Souer E, and Schat H. Enhanced arsenate reduction by a CDC25-like tyrosine phosphatase explains increased phytochelatin accumulation in arsenate-tolerant Holcus lanatus. Plant J. 2006 Mar;45(6):917-29. DOI:10.1111/j.1365-313X.2005.02651.x |
12. Dhankher OP, Rosen BP, McKinney EC, and Meagher RB. Hyperaccumulation of arsenic in the shoots of Arabidopsis silenced for arsenate reductase (ACR2). Proc Natl Acad Sci U S A. 2006 Apr 4;103(14):5413-8. DOI:10.1073/pnas.0509770102 |
13. Duan GL, Zhu YG, Tong YP, Cai C, and Kneer R. Characterization of arsenate reductase in the extract of roots and fronds of Chinese brake fern, an arsenic hyperaccumulator. Plant Physiol. 2005 May;138(1):461-9. DOI:10.1104/pp.104.057422 |
14. Duan GL, Zhou Y, Tong YP, Mukhopadhyay R, Rosen BP, and Zhu YG. A CDC25 homologue from rice functions as an arsenate reductase. New Phytol. 2007;174(2):311-321. DOI:10.1111/j.1469-8137.2007.02009.x |
15. Ellis DR, Gumaelius L, Indriolo E, Pickering IJ, Banks JA, and Salt DE. A novel arsenate reductase from the arsenic hyperaccumulating fern Pteris vittata. Plant Physiol. 2006 Aug;141(4):1544-54. DOI:10.1104/pp.106.084079 |
16. Yin X, Wang L, Duan G, and Sun G. Characterization of arsenate transformation and identification of arsenate reductase in a green alga Chlamydomonas reinhardtii. J Environ Sci (China). 2011;23(7):1186-93. DOI:10.1016/s1001-0742(10)60492-5 |
17. Zhou Y, Messier N, Ouellette M, Rosen BP, and Mukhopadhyay R. Leishmania major LmACR2 is a pentavalent antimony reductase that confers sensitivity to the drug pentostam. J Biol Chem. 2004 Sep 3;279(36):37445-51. DOI:10.1074/jbc.M404383200 |