Prenylcysteine α-Carboxyl Methyltransferase in Suspension-Cultured Tobacco Cells1

Crowell, Dring N.; Sen, Stephanie E.; Randall, Stephen K.

doi:10.1104/pp.118.1.115

Cited by 31 publications

(23 citation statements)

References 66 publications

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“…Membrane aliquots were stored at 2808C in the presence of 15% glycerol. ICMT assays were performed essentially as described (Hrycyna and Clarke, 1990;Crowell et al, 1998) in the presence of 60 mg of membrane protein, S-adenosyl-L-[ 3 H-methyl]methionine (GE Healthcare Life Sciences) as a methyl donor (24 mM, 2.5 Ci/mmol, 60 mCi/mL), 200 mM AFC or AGGC as a methyl acceptor (200 mM AGC was used as a negative control), and 100 mM HEPES (pH 7.0), in a total volume of 50 mL. Stock solutions of AFC, AGGC, and AGC (BioMol) were prepared in DMSO at a concentration of 10 mM.…”

Section: Icmt Assaysmentioning

confidence: 99%

“…CDP, cytidine diphosphate; CTD, cytidine triphosphate; CHO, aldehyde; OPP, diphosphate; SAH, S-adenosyl-L-homocysteine; SAM, S-adenosyl-L-methionine. the newly formed C terminus is methylated (Figure 1) (Hancock et al, 1991;Sapperstein et al, 1994;Crowell et al, 1998;Bergo et al, 2000;Rodríguez-Concepció n et al, 2000). Two distinct isoprenylcysteine methyltransferase (ICMT) enzymes, encoded by the STE14A and STE14B (ICMT) genes, catalyze the methylation of C-terminal isoprenylcysteines in Arabidopsis (Crowell et al, 1998;Rodríguez-Concepció n et al, 2000;Crowell and Kennedy, 2001;Chary et al, 2002). The products of these genes, expressed as recombinant proteins in Saccharomyces cerevisiae, have been shown to methylate N-acetyl-S-trans,trans-farnesyl-L-cysteine (AFC) and N-acetyl-S-all trans-geranylgeranyl-L-cysteine (AGGC), which are biologically relevant isoprenylcysteine methyl acceptor substrates, but not N-acetyl-S-trans-geranyl-L-cysteine (AGC), a biologically irrelevant isoprenylcysteine substrate .…”

Section: Introductionmentioning

confidence: 99%

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Isoprenylcysteine Methylation and Demethylation Regulate Abscisic Acid Signaling inArabidopsis

et al. 2008

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Isoprenylated proteins bear an isoprenylcysteine methyl ester at the C terminus. Although isoprenylated proteins have been implicated in meristem development and negative regulation of abscisic acid (ABA) signaling, the functional role of the terminal methyl group has not been described. Here, we show that transgenic Arabidopsis thaliana plants overproducing isoprenylcysteine methyltransferase (ICMT) exhibit ABA insensitivity in stomatal closure and seed germination assays, establishing ICMT as a negative regulator of ABA signaling. By contrast, transgenic plants overproducing isoprenylcysteine methylesterase (ICME) exhibit ABA hypersensitivity in stomatal closure and seed germination assays. Thus, ICME is a positive regulator of ABA signaling. To test the hypothesis that ABA signaling is under feedback regulation at the level of isoprenylcysteine methylation, we examined the effect of ABA on ICMT and ICME gene expression. Interestingly, ABA induces ICME gene expression, establishing a positive feedback loop whereby ABA promotes ABA responsiveness of plant cells via induction of ICME expression, which presumably results in the demethylation and inactivation of isoprenylated negative regulators of ABA signaling. These results suggest strategies for metabolic engineering of crop species for drought tolerance by targeted alterations in isoprenylcysteine methylation.

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Section: Icmt Assaysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Isoprenylcysteine Methylation and Demethylation Regulate Abscisic Acid Signaling inArabidopsis

et al. 2008

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“…a-carboxyl methyltransferase, encoded by the STE14 gene, catalyze the proteolysis and carboxyl methylation of prenylated proteins in Saccharomyces cerevisiae (Hrycyna et al, 1991;Sapperstein et al, 1994;Boyartchuk et al, 1997;Tam et al, 1998). Moreover, orthologs of these genes have been described in Arabidopsis, including AtSTE24, AtFACE-2 (an ortholog of RCE1), AtSTE14A, and AtSTE14B (Crowell et al, 1998;Crowell and Kennedy, 2001;Bracha et al, 2002;Narasimha Chary et al, 2002;Cadiñ anos et al, 2003). Thus, protein prenylation, proteolysis, and methylation are conserved protein modifications in eukaryotes.…”

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confidence: 99%

Protein Geranylgeranyltransferase I Is Involved in Specific Aspects of Abscisic Acid and Auxin Signaling in Arabidopsis

Johnson

Chary²,

Chernoff³

et al. 2005

Plant Physiology

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(Q.Z., M.P.R.)Arabidopsis (Arabidopsis thaliana) mutants lacking a functional ERA1 gene, which encodes the b-subunit of protein farnesyltransferase (PFT), exhibit pleiotropic effects that establish roles for protein prenylation in abscisic acid (ABA) signaling and meristem development. Here, we report the effects of T-DNA insertion mutations in the Arabidopsis GGB gene, which encodes the b-subunit of protein geranylgeranyltransferase type I (PGGT I). Stomatal apertures of ggb plants were smaller than those of wild-type plants at all concentrations of ABA tested, suggesting that PGGT I negatively regulates ABA signaling in guard cells. However, germination of ggb seeds in response to ABA was similar to the wild type. Lateral root formation in response to exogenous auxin was increased in ggb seedlings compared to the wild type, but no change in auxin inhibition of primary root growth was observed, suggesting that PGGT I is specifically involved in negative regulation of auxin-induced lateral root initiation. Unlike era1 mutants, ggb mutants exhibited no obvious developmental phenotypes. However, era1 ggb double mutants exhibited more severe developmental phenotypes than era1 mutants and were indistinguishable from plp mutants lacking the shared a-subunit of PFT and PGGT I. Furthermore, overexpression of GGB in transgenic era1 plants partially suppressed the era1 phenotype, suggesting that the relatively weak phenotype of era1 plants is due to partial redundancy between PFT and PGGT I. These results are discussed in the context of Arabidopsis proteins that are putative substrates of PGGT I.Protein prenylation involves the formation of a thioether bond between a farnesyl (C15) or geranylgeranyl (C20) group and a C-terminal Cys residue (Clarke, 1992;Zhang and Casey, 1996). This posttranslational modification promotes protein-membrane and, in many cases, protein-protein interactions. Three protein prenyltransferases are known to catalyze protein prenylation in plants and other eukaryotes: (1) a heterodimeric protein farnesyltransferase (PFT) that consists of a-and b-subunits and transfers a farnesyl group from farnesyl pyrophosphate (FPP) to proteins bearing a C-terminal CaaX motif, where ''C'' is Cys, ''a'' is often an aliphatic amino acid, and ''X'' is generally Met, Ala, Gln, Ser, or Cys; (2) a heterodimeric type I protein geranylgeranyltransferase (PGGT I) that shares a common a-subunit with PFT but possesses a distinct b-subunit and transfers a geranylgeranyl group from geranylgeranyl pyrophosphate (GGPP) to proteins bearing a C-terminal CaaX motif, where ''X'' is Leu; and (3) a heterotrimeric type II protein geranylgeranyltransferase (PGGT II or Rab PGGT) that consists of distinct a-and b-subunits, as well as a third subunit called the Rab escort protein, and transfers a geranylgeranyl group from GGPP to Rab protein substrates (Clarke, 1992;Zhang and Casey, 1996;Crowell, 2000). PFT subunits have been identified and characterized from pea (Pisum sativum; Yang et al., 1993;Qian et al., 1996), tomato (Lycopersicon ...

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“…Plant protein extracts were shown to contain PCM activity (4,25), and a plant gene encoding PCM (AtPCM) was cloned (4). Transiently expressed GFP-AtPCM fusion protein accumulated in a subfraction of the endomembrane system and inhibition of the methyltransferase activity resulted in accumulation of CaM53, a prenylated plant protein, in the same subcellular fraction (4).…”

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The Arabidopsis AtSTE24 Is a CAAXProtease with Broad Substrate Specificity

Bracha

Lavy

Yalovsky

2002

Journal of Biological Chemistry

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Following prenylation, the proteins are subject to two prenyl-dependent modifications at their C-terminal end, which are required for their subcellular targeting. First, the three C-terminal residues of the CAAX box prenylation signaling motif are removed, which is followed by methylation of the free carboxyl group of the prenyl cysteine moiety. An Arabidopsis homologue of the yeast CAAX protease STE24 (AFC1) was cloned and expressed in rce1⌬ ste24⌬ mutant yeast to demonstrate functional complementation. The petunia calmodulin CaM53 is a prenylated protein terminating in a CTIL CAAX box. Coupled methylation proteolysis assays demonstrated the processing of CaM53 by AtSTE24. In addition, AtSTE24 promoted plasma membrane association of the GFP-RacU88402 fusion protein, which terminates with a CLLM CAAX box. Interestingly, a plant homologue of the second and major CAAX protease in yeast and animal cells, RCE1, was not identified despite the availability of vast amounts of sequence data. Taken together, these data suggest that AtSTE24 may process several prenylated proteins in plant cells, unlike its yeast homologue, which processes only a-mating factor, and its mammalian homologue, for which prenyl-CAAX substrates have not been established. Transient expression of GFPAtSTE24 in leaf epidermal cells of Nicotiana benthamiana showed that AtSTE24 is exclusively localized in the endoplasmic reticulum, suggesting that prenylated proteins in plants are first targeted to the endoplasmic reticulum following their prenylation.

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Prenylcysteine α-Carboxyl Methyltransferase in Suspension-Cultured Tobacco Cells1

Abstract: Isoprenoid protein modifications are necessary for the interaction of certain proteins with membranes and/or other proteins (Hancock et al

Cited by 31 publications

References 66 publications

Isoprenylcysteine Methylation and Demethylation Regulate Abscisic Acid Signaling inArabidopsis

Isoprenylcysteine Methylation and Demethylation Regulate Abscisic Acid Signaling inArabidopsis

Protein Geranylgeranyltransferase I Is Involved in Specific Aspects of Abscisic Acid and Auxin Signaling in Arabidopsis

The Arabidopsis AtSTE24 Is a CAAXProtease with Broad Substrate Specificity

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