Difference between revisions of "Phosphatase Subfamily Acr2"
(→Acr2, phosphatase or arsenate reductase?) |
(→Acr2, phosphatase or arsenate reductase?) |
||
| Line 2: | Line 2: | ||
=== Acr2, phosphatase or arsenate reductase? === | === 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 ('''[[Yeast_Gene_MIH1|MIH1]]''' and '''[[Yeast_Gene_ARR2|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). | + | 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 ('''[[Yeast_Gene_MIH1|MIH1]]''' and '''[[Yeast_Gene_ARR2|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'' <cite>rosen-10</cite>. |
==== A brief of arsentate reductase ==== | ==== A brief of arsentate reductase ==== | ||
Revision as of 05:39, 28 May 2014
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
Error fetching PMID 9812373:
Error fetching PMID 10801893:
Error fetching PMID 11461905:
Error fetching PMID 15329414:
Error fetching PMID 15329414:
Error fetching PMID 15720653:
Error fetching PMID 16507083:
Error fetching PMID 16567632:
Error fetching PMID 22879969:
Error fetching PMID 17388894:
Error fetching PMID 15834011:
Error fetching PMID 16766666:
Error fetching PMID 22125913:
Error fetching PMID 16949857:
Error fetching PMID 15220340:
- Error fetching PMID 19382206:
- Error fetching PMID 22879969:
- Error fetching PMID 9812373:
- Error fetching PMID 10801893:
- Error fetching PMID 11461905:
- Error fetching PMID 15329414:
- Error fetching PMID 15329414:
- Error fetching PMID 15720653:
- Error fetching PMID 16949857:
- Error fetching PMID 16507083:
- Error fetching PMID 16567632:
- Error fetching PMID 15834011:
- Error fetching PMID 17388894:
- Error fetching PMID 16766666:
- Error fetching PMID 22125913:
- Error fetching PMID 15220340:
