1
|
Kim HB, Oh CJ, Park YC, Lee Y, Choe S, An CS, Choi SB. Comprehensive analysis of AHL homologous genes encoding AT-hook motif nuclear localized protein in rice. BMB Rep 2012; 44:680-5. [PMID: 22027003 DOI: 10.5483/bmbrep.2011.44.10.680] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The AT-hook motif is a small DNA-binding protein motif that has been found in the high mobility group of non-histone chromosomal proteins. The Arabidopsis genome contains 29 genes encoding the AT-hook motif DNA-binding protein (AHL). Recent studies of Arabidopsis genes (AtAHLs) have revealed that they might play diverse functional roles during plant growth and development. In this report, we mined 20 AHL genes (OsAHLs) from the rice genome database using AtAHL genes as queries and characterized their molecular features. A phylogenetic tree revealed that OsAHL proteins can be classified into 2 evolutionary clades. Tissue expression pattern analysis revealed that all of the OsAHL genes might be functionally expressed genes with 3 distinct expression patterns. Nuclear localization analysis using transgenic Arabidopsis showed that several OsAHL proteins are exclusively localized in the nucleus, indicating that they may act as architectural transcription factors to regulate expression of their target genes during plant growth and development.
Collapse
Affiliation(s)
- Ho Bang Kim
- The Natural Science Research Institute, Myongji University, Yongin, Korea.
| | | | | | | | | | | | | |
Collapse
|
2
|
The maize HMGA protein is localized to the nucleolus and can be acetylated in vitro at its globular domain, and phosphorylation by CDK reduces its binding activity to AT-rich DNA. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:751-7. [DOI: 10.1016/j.bbagrm.2009.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 09/16/2009] [Indexed: 11/23/2022]
|
3
|
Launholt D, Grønlund JT, Nielsen HK, Grasser KD. Overlapping expression patterns among the genes encodingArabidopsischromosomal high mobility group (HMG) proteins. FEBS Lett 2007; 581:1114-8. [PMID: 17316617 DOI: 10.1016/j.febslet.2007.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 02/07/2007] [Accepted: 02/07/2007] [Indexed: 11/30/2022]
Abstract
High mobility group (HMG) proteins are usually considered ubiquitous components of the eukaryotic chromatin. Using HMG gene promoter-GUS reporter gene fusions we have examined the expression of the reporter gene in transgenic Arabidopsis plants. These experiments have revealed that the different HMGA and HMGB promoters display overlapping patterns of activity, but they also show tissue- and developmental stage-specific differences. Moreover, leader introns that are present in some of the HMGB genes can modulate reporter gene expression. The differential HMG gene expression supports the view that the various HMG proteins serve partially different architectural functions in plant chromatin.
Collapse
Affiliation(s)
- Dorte Launholt
- Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark
| | | | | | | |
Collapse
|
4
|
Lafleuriel J, Degroote F, Depeiges A, Picard G. A reciprocal translocation, induced by a canonical integration of a single T-DNA, interrupts the HMG-I/Y Arabidopsis thaliana gene. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2004; 42:171-179. [PMID: 15051040 DOI: 10.1016/j.plaphy.2004.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Accepted: 01/19/2004] [Indexed: 05/24/2023]
Abstract
Major chromosomal rearrangements occur during Arabidopsis thaliana T-DNA transformation. They generally result from interactions between multiple T-DNA copies during the integration process or from aborted integration events. We report here a reciprocal translocation associated with the integration of a single T-DNA which otherwise shows all the characteristic features of a canonical integration event. The exchanged fragments roughly correspond to half of the left arm of chromosome 1 and to two thirds of the right arm of chromosome 2. The chromosome 1 breakpoint maps close to position 23.6 cM and interrupts the coding sequence of the HMG-I/Y gene, which is present at a single copy in the Arabidopsis genome and encodes a non-histone chromosomal protein putatively involved in regulation of gene expression. The chromosome 2 breakpoint maps close to position 33.6 cM, and is located 419 bp upstream of a gene encoding a putative homeodomain transcription factor. Homozygotes for the translocation display a severe phenotype with major developmental abnormalities and total sterility, while heterozygotes are fertile, most of them showing a wild-type phenotype. Among the six possible unbalanced genotypic classes, four are entirely lethal while only a few individuals from the two others survive. Analysis of relations between phenotypes and genotypes strongly suggests that the major phenotypic alterations observed do not result from inactivation of the HMG-I/Y gene.
Collapse
Affiliation(s)
- Jacqueline Lafleuriel
- GEEM-BIOMOVE, Université Blaise-Pascal, CNRS UMR 6547, 24, avenue des Landais, 63177 Aubière cedex, France
| | | | | | | |
Collapse
|
5
|
Zhang W, Wu Q, Pwee KH, Manjunatha Kini R. Interaction of wheat high-mobility-group proteins with four-way-junction DNA and characterization of the structure and expression of HMGA gene. Arch Biochem Biophys 2003; 409:357-66. [PMID: 12504903 DOI: 10.1016/s0003-9861(02)00630-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Plant high-mobility-group (HMG) chromosomal proteins are the most abundant and ubiquitous nonhistone proteins found in the nuclei of higher eukaryotes. There are only two families of HMG proteins, namely, HMGA and HMGB in plants. The cDNA encoding wheat HMGa protein was isolated and characterized. Wheat HMGA cDNA encodes a protein of 189 amino acid residues. At its N terminus, there is a histone H1-like structure, which is a common feature of plant HMGA proteins, followed by four AT-hook motifs. Polymerase chain reaction results show that the gene contains a single intron of 134 bp. All four AT-hook motifs are encoded by the second exon. Northern blot results show that the expression of HMGA gene is much higher in organs undergoing active cell proliferation. Gel retardation analysis show that wheat HMGa, b, c and histone H1 bind to four-way-junction DNA with high binding affinity, but affinity is dramatically reduced with increasing Mg(2+) and Na(+) ion concentration. Competition binding studies show that proteins share overlapping binding sites on four-way-junction DNA. HMGd does not bind to four-way-junction DNA.
Collapse
Affiliation(s)
- Wensheng Zhang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, 117543, Singapore, Singapore
| | | | | | | |
Collapse
|
6
|
Gupta R, Mould RM, He Z, Luan S. A chloroplast FKBP interacts with and affects the accumulation of Rieske subunit of cytochrome bf complex. Proc Natl Acad Sci U S A 2002; 99:15806-11. [PMID: 12424338 PMCID: PMC137797 DOI: 10.1073/pnas.222550399] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Immunophilins are intracellular receptors of the immunosuppressants cyclosporin A, FK506, and rapamycin. Although all immunophilins possess peptidyl-prolyl isomerase activity and are identified from a wide range of organisms, little is known about their cellular functions. We report the characterization and functional analysis of an FK506 and rapamycin-binding protein (AtFKBP13) from Arabidopsis. The AtFKBP13 protein is synthesized as a precursor that is imported into chloroplasts and processed to the mature form located in the thylakoid lumen, as shown by chloroplast import assays and Western blot analysis. Experiments show that AtFKBP13 is translocated across the thylakoid membrane by the DeltapH-dependent pathway. Yeast two-hybrid screening identified Rieske FeS protein, a subunit of the cytochrome bf complex in the photosynthetic electron transport chain, as an interacting partner for AtFKBP13. Both yeast two-hybrid and in vitro protein-protein interaction assays showed that the precursor, but not the mature form, of AtFKBP13 interacted with Rieske protein, suggesting that interaction between the two proteins occurs along the import pathway. When AtFKBP13 expression was suppressed by RNA interference method, the level of Rieske protein was significantly increased in the transgenic plants.
Collapse
Affiliation(s)
- Rajeev Gupta
- Department of Plant and Microbial Biology, University of California, Berkeley 94720, USA
| | | | | | | |
Collapse
|
7
|
Reisdorf-Cren M, Carrayol E, Tercé-Laforgue T, Hirel B. A novel HMG A-like protein binds differentially to the AT-rich regions located in the far distal and proximal parts of a soybean glutamine synthetase gene (GS15) promoter. PLANT & CELL PHYSIOLOGY 2002; 43:1006-16. [PMID: 12354918 DOI: 10.1093/pcp/pcf123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In soybean (Glycine max L.) ammonium provided externally or as the result of symbiotic nitrogen fixation stimulates the transcription of GS15, a gene encoding cytosolic glutamine synthetase. Strong constitutive positive expression (SCPE), silencer-like and organ-specific elements, located respectively in the distal, the central and the proximal region of the promoter are required to control the ammonium responsiveness of the gene expression [Tercé-Laforgue et al. (1999) Plant Mol. Biol. 39: 551]. It was hypothesized that the correct spatial conformation of the promoter permitted the cooperative action of these three cis-acting elements. Further investigations were therefore required to ascertain this hypothesis. A nodule nuclear protein, binding to a 66 bp AT-rich DNA fragment containing a 13 bp AT-rich repeated sequence (AT-1) and located just downstream of the SCPE element, was identified using a gel retardation assay. A cDNA clone likely to code for this protein was isolated using the yeast one-hybrid system. It encodes a novel DNA binding protein (AT-1SNBP) similar to HMG A proteins but exhibiting a higher molecular weight. AT-1SNBP appears to be encoded by a single gene that is expressed in roots, root nodules and leaves of soybean. Since two other 13 bp AT-rich repeated sequences (AT-2 and AT-3) were localized in the organ-specific element, we have quantified the binding affinity of AT-1SNBP to these sequences. We demonstrate that AT-1SNBP binds differentially to DNA fragments containing AT-1, AT-2 and AT-3 and that its binding affinity depends on the presence of adjacent sequences. This result suggests that AT-1SNBP may be an architectural protein involved in maintaining the spatial conformation of the GS15 promoter, thus facilitating the interaction between the distal and proximal regulatory elements.
Collapse
MESH Headings
- AT Rich Sequence/genetics
- AT-Hook Motifs/genetics
- Amino Acid Sequence
- Base Sequence
- Bradyrhizobium/growth & development
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cytosol/enzymology
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA, Plant/chemistry
- DNA, Plant/genetics
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Plant/drug effects
- Genes, Plant/genetics
- Glutamate-Ammonia Ligase/genetics
- Glutamate-Ammonia Ligase/metabolism
- HMGA Proteins/genetics
- HMGA Proteins/metabolism
- Lotus/enzymology
- Lotus/genetics
- Lotus/microbiology
- Molecular Sequence Data
- Plants, Genetically Modified
- Promoter Regions, Genetic
- Quaternary Ammonium Compounds/pharmacology
- Rhizobium/growth & development
- Sequence Analysis, DNA
- Sequence Deletion
- Soybean Proteins/genetics
- Soybean Proteins/metabolism
- Glycine max/enzymology
- Glycine max/genetics
- Glycine max/microbiology
- Transcription Factors/genetics
- Two-Hybrid System Techniques
Collapse
Affiliation(s)
- Michèle Reisdorf-Cren
- Laboratoire de la Nutrition Azotée des Plantes, INRA, centre de Versailles, Route de Saint Cyr, F-78026 Versailles Cedex, France.
| | | | | | | |
Collapse
|
8
|
Knight JS, Duckett CM, Sullivan JA, Walker AR, Gray JC. Tissue-specific, light-regulated and plastid-regulated expression of the single-copy nuclear gene encoding the chloroplast Rieske FeS protein of Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2002; 43:522-31. [PMID: 12040099 DOI: 10.1093/pcp/pcf062] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The single-copy PetC gene encoding the chloroplast Rieske FeS protein of Arabidopsis thaliana consists of five exons interrupted by four introns and encodes a protein of 229 amino acid residues with extensive sequence similarity to the chloroplast Rieske proteins of other higher plants. The N-terminal 50 amino acid residues constitute a presequence for targeting to the chloroplast and the remaining 179 amino acid residues make up the mature protein. Three of the introns are in identical positions in the PetC gene of Chlamydomonas reinhardtii, suggesting that they are of ancient origin. RNA-blot hybridisation showed that the gene was expressed in shoots, but not roots, and was light regulated and repressed by sucrose. The expression of chimeric genes consisting of PetC promoter fragments fused to the beta-glucuronidase (GUS) reporter gene was examined in A. thaliana and tobacco. In A. thaliana, GUS activity was detected in leaves, stems, flowers and siliques, but not in roots, and showed a strong correlation with the presence of chloroplasts. In transgenic tobacco, low levels of GUS activity were also detected in light-exposed roots. GUS activity in transgenic tobacco seedlings was light regulated and was decreased by norflurazon in the light suggesting regulation of PetC expression by plastid signals.
Collapse
Affiliation(s)
- Julie S Knight
- Department of Plant Sciences and Cambridge Centre for Molecular Recognition, University of Cambridge, Downing Street, Cambridge CB2 3EA, U.K
| | | | | | | | | |
Collapse
|
9
|
Reeves R, Beckerbauer L. HMGI/Y proteins: flexible regulators of transcription and chromatin structure. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1519:13-29. [PMID: 11406267 DOI: 10.1016/s0167-4781(01)00215-9] [Citation(s) in RCA: 272] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The mammalian HMGI/Y (HMGA) non-histone proteins participate in a wide variety of cellular processes including regulation of inducible gene transcription, integration of retroviruses into chromosomes and the induction of neoplastic transformation and promotion of metastatic progression of cancer cells. Recent advances have contributed greatly to our understanding of how the HMGI/Y proteins participate in the molecular mechanisms underlying these biological events. All members of the HMGI/Y family of 'high mobility group' proteins are characterized by the presence of multiple copies of a conserved DNA-binding peptide motif called the 'AT hook' that preferentially binds to the narrow minor groove of stretches of AT-rich sequence. The mammalian HMGI/Y proteins have little, if any, secondary structure in solution but assume distinct conformations when bound to substrates such as DNA or other proteins. Their intrinsic flexibility allows the HMGI/Y proteins to participate in specific protein-DNA and protein-protein interactions that induce both structural changes in chromatin substrates and the formation of stereospecific complexes called 'enhanceosomes' on the promoter/enhancer regions of genes whose transcription they regulate. The formation of such regulatory complexes is characterized by reciprocal inductions of conformational changes in both the HMGI/Y proteins themselves and in their interacting substrates. It may well be that the inherent flexibility of the HMGI/Y proteins, combined with their ability to undergo reversible disordered-to-ordered structural transitions, has been a significant factor in the evolutionary selection of these proteins for their functional role(s) in cells.
Collapse
Affiliation(s)
- R Reeves
- Department of Biochemistry/Biophysics, School of Molecular Biosciences, Washington State University, Pullman, WA 99164-4660, USA.
| | | |
Collapse
|
10
|
Masek T, Smykal P, Janotova I, Honys D, Capkova V, Pechan PM. Isolation of a Brassica napus L. cDNA encoding a putative high-mobility-group HMG I/Y protein. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2000; 159:197-204. [PMID: 11074272 DOI: 10.1016/s0168-9452(00)00329-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A cDNA encoding a high-mobility-group protein has been isolated from a microspore-specific library of Brassica napus. The 930 bp cDNA contains a 612 bp open reading frame encoding a protein of 203 amino acids residues exhibiting significant homology to HMG-I/Y protein from Arabidopsis thaliana (62%). The predicted protein contains four copies of the 'AT-hook' motif which is involved in binding A/T-rich DNA. Southern blotting indicates that the HMG-I/Y gene is a single-copy gene in B. napus. Transcription of the HMG-I/Y gene was detected in all tissues examined, with the highest expression in pollen-derived embryos. In situ localization studies of flower organs indicate the transcript to be preferentially located in petals and sepals. Subcellular localization analysis performed during pollen development showed that the transcript of the HMG-I/Y gene is predominantly associated with polysomes.
Collapse
Affiliation(s)
- T Masek
- Department of Plant Physiology, Faculty of Science, Charles University, Vinicna 5, CZ 128 44, Prague, Czech Republic
| | | | | | | | | | | |
Collapse
|
11
|
Liu L, White MJ, MacRae TH. Transcription factors and their genes in higher plants functional domains, evolution and regulation. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 262:247-57. [PMID: 10336605 DOI: 10.1046/j.1432-1327.1999.00349.x] [Citation(s) in RCA: 224] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A typical plant transcription factor contains, with few exceptions, a DNA-binding region, an oligomerization site, a transcription-regulation domain, and a nuclear localization signal. Most transcription factors exhibit only one type of DNA-binding and oligomerization domain, occasionally in multiple copies, but some contain two distinct types. DNA-binding regions are normally adjacent to or overlap with oligomerization sites, and their combined tertiary structure determines critical aspects of transcription factor activity. Pairs of nuclear localization signals exist in several transcription factors, and basic amino acid residues play essential roles in their function, a property also true for DNA-binding domains. Multigene families encode transcription factors, with members either dispersed in the genome or clustered on the same chromosome. Distribution and sequence analyses suggest that transcription factor families evolved via gene duplication, exon capture, translocation, and mutation. The expression of transcription factor genes in plants is regulated at transcriptional and post-transcriptional levels, while the activity of their protein products is modulated post-translationally. The purpose of this review is to describe the domain structure of plant transcription factors, and to relate this information to processes that control the synthesis and action of these proteins.
Collapse
Affiliation(s)
- L Liu
- Department of Biology, University, Halifax, Nova Scotia, Canada.
| | | | | |
Collapse
|
12
|
Taoka K, Kaya H, Nakayama T, Araki T, Meshi T, Iwabuchi M. Identification of three kinds of mutually related composite elements conferring S phase-specific transcriptional activation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1999; 18:611-23. [PMID: 10417712 DOI: 10.1046/j.1365-313x.1999.00486.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Conservation of the Oct motif (CGCGGATC) is a remarkable feature of plant histone gene promoters. Many of the Oct motifs are paired with a distinct motif, Hex, TCA or CCAAT-box, constituting the type I element (CCACGTCANCGATCCGCG), type II element (TCACGCGGATC) and type III element (GATCCGCG-N14-ACCAATCA). To clarify the roles of these Oct-containing composite elements (OCEs) in cell cycle-dependent and tissue-specific expression, we performed gain-of-function experiments with transgenic tobacco cell lines and plants harboring a derivative of the 35S core promoter/beta-glucuronidase fusion gene in which three or four copies of an OCE had been placed upstream. Although their activities were slightly different, results showed that each of the three types of OCEs could confer the ability to direct S phase-specific expression on a heterologous promoter. In transgenic plants, the type I and III elements exhibited a similar activity, directing expression in meristematic tissues, whereas the activity of the type II element appeared to be restricted to young cotyledons and maturating guard cells. Mutational analyses demonstrated that the co-operation of Oct with another module (Hex, TCA or CCAAT-box) was absolutely required for both temporal and spatial regulation. Thus, OCEs play a pivotal role in regulation of the expression of plant histone genes.
Collapse
Affiliation(s)
- K Taoka
- Department of Botany, Graduate School of Science, Kyoto University, Japan
| | | | | | | | | | | |
Collapse
|
13
|
Krech AB, Wulff D, Grasser KD, Feix G. Plant chromosomal HMGI/Y proteins and histone H1 exhibit a protein domain of common origin. Gene 1999; 230:1-5. [PMID: 10196467 DOI: 10.1016/s0378-1119(99)00067-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The chromosomal high-mobility-group (HMG) proteins of the HMGI/Y family interact with A/T-rich stretches in duplex DNA, and are considered assistant factors in transcriptional regulation. A cDNA encoding an HMGI/Y protein of 190 amino acid residues was isolated from maize and characterized. Like other plant HMGI/Y proteins, the maize HMGI/Y protein contains four copies of the AT-hook DNA-binding motif and an amino-terminal 'histone H1-like region' with a similarity to the globular domain of H1. The maize hmgi/y gene that was isolated from a genomic DNA library contains a single intron that is localized in the region of sequence similarity to histone H1. Interestingly, the genes encoding plant H1 contain an intron at exactly the same relative position, indicating an evolutionary relationship of the plant genes encoding HMGI/Y and H1 proteins.
Collapse
Affiliation(s)
- A B Krech
- Institut für Biologie III, Albert-Ludwigs-Universität Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | | | | | | |
Collapse
|
14
|
Gupta R, Huang Y, Kieber J, Luan S. Identification of a dual-specificity protein phosphatase that inactivates a MAP kinase from Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1998; 16:581-589. [PMID: 10036776 DOI: 10.1046/j.1365-313x.1998.00327.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Mitogen-activated protein kinases (MAPKs) play a key role in plant responses to stress and pathogens. Activation and inactivation of MAPKs involve phosphorylation and dephosphorylation on both threonine and tyrosine residues in the kinase domain. Here we report the identification of an Arabidopsis gene encoding a dual-specificity protein phosphatase capable of hydrolysing both phosphoserine/threonine and phosphotyrosine in protein substrates. This enzyme, designated AtDsPTP1 (Arabidopsis thaliana dual-specificity protein tyrosine phosphatase), dephosphorylated and inactivated AtMPK4, a MAPK member from the same plant. Replacement of a highly conserved cysteine by serine abolished phosphatase activity of AtDsPTP1, indicating a conserved catalytic mechanism of dual-specificity protein phosphatases from all eukaryotes.
Collapse
Affiliation(s)
- R Gupta
- Department of Plant and Microbial Biology, University of California at Berkeley 94720, USA
| | | | | | | |
Collapse
|