Differential expression of two functional serine/threonine protein kinases from soyabean that have an unusual acidic domain at the carboxy terminus

Yoon, Hae Won; Kim, M C; Shin, Pyeong-Soo; Kim, J S; Kim, Chang-Yub; Lee, S Y; Hwang, Inhwan; Bahk, Jeong Dong; Hong, Jong Chan; Han, Chun-Sheng; Cho, M J

doi:10.1007/s004380050507

Cited by 37 publications

(42 citation statements)

References 48 publications

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“…SAC3 is a type 2 SNF1-related kinase (SnRK2) and is similar to family kinases found in vascular plants. Several of these SnRK2-encoding transcripts increase in abundance in response to environmental stresses (Anderberg and WalkerSimmons, 1992;Park et al, 1993;Yoon et al, 1997), but the function of most of the SnRK2 proteins found in plants have yet to be elucidated. Arabidopsis contains at least 12 SnRK2 proteins that have significant similarity (49% amino acid identity and 60% amino acid similarity over most of the protein) with SAC3.…”

Section: Regulation Of the Cys Biosynthetic Pathwaymentioning

confidence: 99%

The sac Mutants of Chlamydomonas reinhardtii Reveal Transcriptional and Posttranscriptional Control of Cysteine Biosynthesis

et al. 2002

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Algae and vascular plants are cysteine (Cys) prototrophs. They are able to import, reduce, and assimilate sulfate into Cys, methionine, and other organic sulfur-containing compounds. Characterization of genes encoding the enzymes required for Cys biosynthesis from the unicellular green alga Chlamydomonas reinhardtii reveals that transcriptional and posttranscriptional mechanisms regulate the pathway. The derived amino acid sequences of the C. reinhardtii genes encoding 5Ј-adenylylsulfate (APS) reductase and serine (Ser) acetyltransferase are orthologous to sequences from vascular plants. The Cys biosynthetic pathway of C. reinhardtii is regulated by sulfate availability. The steady-state level of transcripts and activity of ATP sulfurylase, APS reductase, Ser acetyltransferase, and O-acetyl-Ser (thiol) lyase increase when cells are deprived of sulfate. The sac1 mutation, which impairs C. reinhardtii ability to acclimate to sulfur-deficient conditions, prevents the increase in accumulation of the transcripts encoding these enzymes and also prevents the increase in activity of all the enzymes except APS reductase. The sac2 mutation, which does not affect accumulation of APS reductase transcripts, blocks the increase in APS reductase activity. These results suggest that APS reductase activity is regulated posttranscriptionally in a SAC2-dependent process.Plants and algae are primary producers. They absorb sunlight and through photosynthesis, convert it into chemical energy stored as carbohydrate. They also import inorganic nutrients from their environment and convert them into biologically active compounds. Photosynthesis and nutrient acquisition are coordinated with growth.Photosynthetic organisms acclimate to nutrientdeficient conditions through a suite of physiological changes that can be classified as general and specific (Harder and Dijkhuizen, 1983;Davies and Grossman, 1998). General responses, which occur when an organism is deprived of any essential nutrient, include a decrease in the rate of photosynthesis, a decrease in or cessation of cell division, and an accumulation of starch or glycogen. Specific changes occur in response to loss of a specific nutrient and are different for each nutrient. Specific responses are those that enable the organism to scavenge the limiting nutrient from internal or external sources, and those that increase the efficiency of nutrient assimilation.The ability to sense and respond to a nutrientlimiting environments is necessary for an organism to successfully compete in natural environments where nutrients are often limiting. However, the mechanisms used to sense nutrient availability and control physiological changes in response to nutrient limitation are largely unknown. We are using the unicellular green alga Chlamydomonas reinhardtii as a model system to study sulfur metabolism and the response to sulfur-deficient conditions. Sulfur is considered a macronutrient because it is required at relatively high levels. Sulfur is a constituent of proteins, lipids, carbohydrates, el...

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Section: Regulation Of the Cys Biosynthetic Pathwaymentioning

confidence: 99%

The sac Mutants of Chlamydomonas reinhardtii Reveal Transcriptional and Posttranscriptional Control of Cysteine Biosynthesis

et al. 2002

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“…nase, SPK4 (Yoon et al, 1997), was used as a marker for soluble proteins. Also, a polyclonal anti-PIPl antibody (a gift of Dr. Schaffner, Ludwig-Maximilians-Universitat) raised against a plasma membrane small-channel protein, PIP1 (Kammerloher et al, 1994), was used as a marker for membrane proteins.…”

Section: Adl1 Is Associated With Membranesmentioning

confidence: 99%

A Dynamin-Like Protein, ADL1, Is Present in Membranes as a High-Molecular-Mass Complex in Arabidopsis thaliana

et al. 1997

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Dynamin, a CTP-binding protein, is involved in endocytosis in animal cells. We found that a dynamin-like protein, ADLl, is present in multiple forms in Arabidopsis leaf tissue. Subcellular fractionation experiments, together with gel-filtration and nondenaturing-gel electrophoresis revealed that most of ADLl is present as a high-molecular-mass complex of 400 to 600 kD in the membrane or pellet fraction, whereas ADLl is present in the soluble fraction as a monomer. l h e subcellular distribution of ADLl is affected by various agents such as Ca2+, cyclosporin A, CTP, and ATP. Ca2+ increases the amount of ADLl present in the membrane fraction, whereas cyclosporin A inhibits the membrane association. Furthermore, CaZ+ and CTP change the migration pattern of ADLl in nondenaturing polyacrylamide gels, indicating that these chemicals influence either the complex formation and/or the conformation of the ADLl complex. Our results demonstrate that ADLl has characteristics that are similar to Dynamin I, which is found in animal cells. Therefore, it is possible that ADLl is also involved in biological processes that require vesicle formation.

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“…Expression of the genes encoding soybean (Glycine max) protein kinases SPK-3 and SPK-4, both members of this subfamily, are induced by dehydration and high salinity (Yoon et al, 1997). Two other soybean protein kinases, i.e.…”

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confidence: 99%

Biochemical Characterization of the Tobacco 42-kD Protein Kinase Activated by Osmotic Stress

et al. 2004

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In tobacco (Nicotiana tabacum), hyperosmotic stress induces rapid activation of a 42-kD protein kinase, referred to as Nicotiana tabacum osmotic stress-activated protein kinase (NtOSAK). cDNA encoding the kinase was cloned and, based on the predicted amino acid sequence, the enzyme was assigned to the SNF1-related protein kinase type 2 (SnRK2) family. The identity of the enzyme was confirmed by immunoprecipitation of the active kinase from tobacco cells subjected to osmotic stress using antibodies raised against a peptide corresponding to the C-terminal sequence of the kinase predicted from the cloned cDNA. A detailed biochemical characterization of NtOSAK purified from stressed tobacco cells was performed. Our results show that NtOSAK is a calcium-independent Ser/Thr protein kinase. The sequence of putative phosphorylation sites recognized by NtOSAK, predicted by the computer program PREDIKIN, resembled the substrate consensus sequence defined for animal and yeast (Saccharomyces cerevisiae) AMPK/SNF1 kinases. Our experimental data confirmed these results, as various targets for AMPK/SNF1 kinases were also efficiently phosphorylated by NtOSAK. A range of protein kinase inhibitors was tested as potential modulators of NtOSAK, but only staurosporine, a rather nonspecific protein kinase inhibitor, was found to abolish the enzyme activity. In phosphorylation reactions, NtOSAK exhibited a preference for Mg 21 over Mn 21 ions and an inability to use GTP instead of ATP as a phosphate donor. The enzyme activity was not modulated by 5#-AMP. To our knowledge, these results represent the first detailed biochemical characterization of a kinase of the SnRK2 family.

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Differential expression of two functional serine/threonine protein kinases from soyabean that have an unusual acidic domain at the carboxy terminus

Cited by 37 publications

References 48 publications

The sac Mutants of Chlamydomonas reinhardtii Reveal Transcriptional and Posttranscriptional Control of Cysteine Biosynthesis

The sac Mutants of Chlamydomonas reinhardtii Reveal Transcriptional and Posttranscriptional Control of Cysteine Biosynthesis

A Dynamin-Like Protein, ADL1, Is Present in Membranes as a High-Molecular-Mass Complex in Arabidopsis thaliana

Biochemical Characterization of the Tobacco 42-kD Protein Kinase Activated by Osmotic Stress

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