Purification and biosynthesis of a derepressible periplasmic arylsulfatase from Chlamydomonas reinhardtii.

Hostos, Eugenio L. de; Togasaki, Robert K.; Grossman, Arthur R.

doi:10.1083/jcb.106.1.29

Cited by 118 publications

(82 citation statements)

References 34 publications

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“…The results showed that although levels of chloroplast RNAs (cpRNAs) remained mainly unchanged under normal conditions, removal of S from the medium resulted in a decrease of 20-90% within 4-8 h and a decrease of 40-60% after 24 h. This decrease was reversible, and transcript abundance recovered to at or above the prestarvation levels after 2 h of S replenishment. This result contrasts with the accumulation of the nuclear ARS1 transcript, which is known to be induced under ϪS conditions (12). As shown in Fig.…”

Section: Abundance Of Several Chloroplast Mrnas Decreases Rapidly Undcontrasting

confidence: 50%

The sulfur acclimation SAC3 kinase is required for chloroplast transcriptional repression under sulfur limitation in Chlamydomonas reinhardtii

Irihimovitch

Stern

2006

Proc. Natl. Acad. Sci. U.S.A.

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Sulfur (S) deprivation responses have been studied extensively in algae and land plants; however, little is known of the signals that link perception of S status to chloroplast gene expression. Here, we have compared the chloroplast S limitation response in WT vs. sac1 and sac3 sulfur acclimation mutants of the green alga Chlamydomonas reinhardtii. We provide evidence that in the WT, chloroplast transcriptional activity rapidly decreases after removal of S from the medium, leading to reduced transcript accumulation. This decrease correlates with reduced abundance of a 70 -like factor, Sig1, which is most likely the unique chloroplast transcription specificity factor. We further show that reduced transcription activity and diminished Sig1 accumulation are mediated by the SAC3 gene product, a putative Snf1-type Ser͞Thr kinase previously shown to have both positive and negative effects on nuclear gene expression. Inclusion of the protein kinase inhibitor 6-dimethylaminopurine during S limitation yielded a pattern of expression that was largely similar to that seen in the sac3 mutant, lending support to the hypothesis that Sac3 kinase activation leads to transcriptional repression and Sig1 proteolysis. The finding that Sac3 regulates chloroplast gene expression suggests that it has a previously unknown role in integrating the S limitation response in multiple subcellular compartments. sigma factor ͉ dimethylaminopurine ͉ RNA polymerase S ulfur (S) is a required macronutrient; it is a constituent of proteins, lipids, electron transport components, and many cell metabolites (1, 2). Most photosynthetic organisms have the capacity to assimilate S as a sulfate anion (SO 4 2Ϫ ) and translocate it to the plastid, where primary S metabolism takes place. In chloroplasts, S is first activated by ATP sulfurylase to form APS (5Ј-adenylyl sulfate), which is a branch-point intermediate. APS can be phosphorylated by APS kinase, and the product can be used in sulfation reactions or to synthesize cysteine and methionine (1). Chloroplasts are thus crucial in the assimilation of S, because ATP and photosynthetic reductant are needed for the first activation and reduction steps.S insufficiency constitutes a serious stress situation for plants and algae, which respond with a series of metabolic adjustments (3, 4). Studies of S deprivation in the green alga Chlamydomonas reinhardtii have shown that limiting S leads to altered photosynthetic performance, reduced levels of photosynthetic proteins, and induction of genes encoding high-affinity S transporters (5, 6). S deprivation also leads to increased accumulation of arylsulfatase (ARS), which releases sulfate anion from esterified organic sulfates, allowing cells to access new sulfur stores (7). These acclimation responses are thought to prevent photodamage under conditions where the cell has limited capacity for metabolism of S-containing compounds, particularly proteins.Several Chlamydomonas mutants that do not respond correctly to S deprivation have been identified based on their inab...

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Section: Abundance Of Several Chloroplast Mrnas Decreases Rapidly Undcontrasting

confidence: 50%

The sulfur acclimation SAC3 kinase is required for chloroplast transcriptional repression under sulfur limitation in Chlamydomonas reinhardtii

Irihimovitch

Stern

2006

Proc. Natl. Acad. Sci. U.S.A.

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“…Cells were grown on solid medium for 4-5 days and the color reactions were allowed to develop for 20-24 hr before the cells were washed from the surface of the medium with deionized water to allow examination of the colored precipitate embedded in the medium. Liquid assays for alkaline phosphatase and arylsulfatase activities were performed as described previously (Lein and Schreiner 1975;de Hostos et al 1988;Quisel et al 1996).…”

Section: Methodsmentioning

confidence: 99%

“…P and S limitation elicit qualitatively similar effects on growth and photosynthesis, differing only in that the responses to S starvation occur more quickly following exposure of cells to medium devoid of S. General responses to nutrient limitation that have been analyzed include the cessation of growth at low cell densities Zhang et al 2002) and a reduction in photosynthetic O 2 evolution, which is mostly a consequence of reduced photosystem II (PS II) 1 activity (Wykoff et al 1998). The specific S-deprivation responses include an elevated rate of extracellular SO 4 2À uptake , secretion of extracellular arylsulfatases (Lein and Schreiner 1975;de Hostos et al 1988), and an increased cellular capacity to assimilate SO 4 2À by increasing levels of enzymes required for cysteine biosynthesis (Ravina et al 2002). Mechanisms for conserving S during limiting conditions include the rapid turnover of sulfolipids and their replacement with phospholipids (Sugimoto et al 2007(Sugimoto et al , 2008, the synthesis of putative cell wall proteins with a very low abundance of S-containing amino acids , and a potential change in the polypeptide composition of light harvesting complexes, favoring the synthesis of complexes with polypeptides containing low levels of sulfur amino acid (Nguyen et al 2008).…”

Section: àmentioning

confidence: 99%

Genetic Interactions Between Regulators of Chlamydomonas Phosphorus and Sulfur Deprivation Responses

et al. 2009

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The Chlamydomonas reinhardtii PSR1 gene is required for proper acclimation of the cells to phosphorus (P) deficiency. P-starved psr1 mutants show signs of secondary sulfur (S) starvation, exemplified by the synthesis of extracellular arylsulfatase and the accumulation of transcripts encoding proteins involved in S scavenging and assimilation. Epistasis analysis reveals that induction of the S-starvation responses in P-limited psr1 cells requires the regulatory protein kinase SNRK2.1, but bypasses the membrane-targeted activator, SAC1. The inhibitory kinase SNRK2.2 is necessary for repression of S-starvation responses during both nutrient-replete growth and P limitation; arylsulfatase activity and S deficiency-responsive genes are partially induced in the P-deficient snrk2.2 mutants and become fully activated in the P-deficient psr1snrk2.2 double mutant. During P starvation, the sac1snrk2.2 double mutants or the psr1sac1snrk2.2 triple mutants exhibit reduced arylsulfatase activity compared to snrk2.2 or psr1snrk2.2, respectively, but the sac1 mutation has little effect on the abundance of S deficiency-responsive transcripts in these strains, suggesting a post-transcriptional role for SAC1 in elicitation of S-starvation responses. Interestingly, P-starved psr1snrk2.2 cells bleach and die more rapidly than wild-type or psr1 strains, suggesting that activation of S-starvation responses during P deprivation is deleterious to the cell. From these results we infer that (i) P-deficient growth causes some internal S limitation, but the S-deficiency responses are normally inhibited during acclimation to P deprivation; (ii) the S-deficiency responses are not completely suppressed in P-deficient psr1 cells and consequently these cells synthesize some arylsulfatase and exhibit elevated levels of transcripts for S-deprivation genes; and (iii) this increased expression is controlled by regulators that modulate transcription of S-responsive genes during S-deprivation conditions. Overall, the work strongly suggests integration of the different circuits that control nutrient-deprivation responses in Chlamydomonas.T HE elements phosphorus (P) and sulfur (S) are essential macronutrients for sustaining life. P is a structural component of nucleic acids and phospholipids, and is a ubiquitous modifier of carbohydrates and proteins, while S is incorporated into sulfolipids, polysaccharides, proteins, cofactors, and a wide variety of important metabolites including S-adenosyl-methionine, glutathione, and phytochelatins. The preferred forms of P and S that are assimilated by plants and microbes are the orthophosphate ion, PO 4 3À (Pi), and the sulfate ion, SO 4 2À

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“…Processes induced by S deprivation in this alga include rapid changes in cell size (Zhang et al, 2002), elevated production of hydrolytic extracellular enzymes (de Hostos et al, 1988;Takahashi et al, 2001), alterations in cell wall structure (Takahashi et al, 2001), changes in the activities and composition of the photosynthetic apparatus (Collier and Grossman, 1992;Wykoff et al, 1998;Zhang et al, 2004;González-Ballester et al, 2010;Cakmak et al, 2012aCakmak et al, , 2012bAksoy et al, 2013), scavenging of S from intracellular structures/molecules, elevated SO 4 22 transport activity Pootakham et al, 2010), and the synthesis of enzymes required for efficient S assimilation (Ravina et al, 1999(Ravina et al, , 2002González-Ballester et al, 2010). Moreover, S-depleted Chlamydomonas cells have been used for microarrayand RNA-seq-based transcript abundance studies (Zhang et al, 2004;Nguyen et al, 2008;González-Ballester et al, 2010), determination of metabolite profiles (Bölling and Fiehn, 2005), and the production of H 2 (Ghirardi et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Critical Function of a Chlamydomonas reinhardtii Putative Polyphosphate Polymerase Subunit during Nutrient Deprivation

2014

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Forward genetics was used to isolate Chlamydomonas reinhardtii mutants with altered abilities to acclimate to sulfur (S) deficiency. The ars76 mutant has a deletion that eliminates several genes, including VACUOLAR TRANSPORTER CHAPERONE1 (VTC1), which encodes a component of a polyphosphate polymerase complex. The ars76 mutant cannot accumulate arylsulfatase protein or mRNA and shows marked alterations in levels of many transcripts encoded by genes induced during S deprivation. The mutant also shows little acidocalcisome formation compared with wild-type, S-deprived cells and dies more rapidly than wild-type cells following exposure to S-, phosphorus-, or nitrogen (N)-deficient conditions. Furthermore, the mutant does not accumulate periplasmic l-amino acid oxidase during N deprivation. Introduction of the VTC1 gene specifically complements the ars76 phenotypes, suggesting that normal acidocalcisome formation in cells deprived of S requires VTC1. Our data also indicate that a deficiency in acidocalcisome function impacts trafficking of periplasmic proteins, which can then feed back on the transcription of the genes encoding these proteins. These results and the reported function of vacuoles in degradation processes suggest a major role of the acidocalcisome in reshaping the cell during acclimation to changing environmental conditions.

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Purification and biosynthesis of a derepressible periplasmic arylsulfatase from Chlamydomonas reinhardtii.

Cited by 118 publications

References 34 publications

The sulfur acclimation SAC3 kinase is required for chloroplast transcriptional repression under sulfur limitation in Chlamydomonas reinhardtii

The sulfur acclimation SAC3 kinase is required for chloroplast transcriptional repression under sulfur limitation in Chlamydomonas reinhardtii

Genetic Interactions Between Regulators of Chlamydomonas Phosphorus and Sulfur Deprivation Responses

Critical Function of a Chlamydomonas reinhardtii Putative Polyphosphate Polymerase Subunit during Nutrient Deprivation

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