Priming and accelerated ageing affect L-isoaspartyl methyltransferase activity in tomato (<i>Lycopersicon esculentum</i>Mill.) seed

Kester, Sharon T.; Geneve, Robert L.; Houtz, Robert L.

doi:10.1093/jxb/48.4.943

Cited by 30 publications

(20 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is in direct contrast to aging of barley seeds, in which PCMT activity decreased with a concomitant increase in l-isoaspartylated proteins over a 17-year period (Mudgett, et al, 1997). Accelerated aging of tomato seeds also lowered PCMT activity, which was correlated with a loss of vigor (Kester et al, 1997). To our knowledge, our study is the first report of an increase in PCMT activity during aging of a vegetative plant tissue, a consequence of the increasing level of damaged peptide substrate.…”

Section: Age-induced Nonenzymatic Modifications Of Tuber Proteinscontrasting

confidence: 54%

“…The reaction was stopped with 40 L of 200 mm NaOH, containing 1% (w/v) SDS, and 60 L of the reaction mixture was spotted onto 1.5-ϫ 8-cm pleated filter paper (3MM, Whatman) suspended in the neck of a 20-mL scintillation vial containing 5 mL of Bio-Safe II scintillation cocktail (Research Products International, Mount Prospect, IL). After 2 h the paper was removed and the [ 3 H]methanol captured in the scintillation solution from the vapor phase was determined (Kester et al, 1997).…”

Section: Pcmt Activitymentioning

confidence: 99%

See 1 more Smart Citation

Age-Induced Protein Modifications and Increased Proteolysis in Potato Seed-Tubers1

1999

View full text Add to dashboard Cite

Long-term aging of potato (Solanum tuberosum) seed-tubers resulted in a loss of patatin (40 kD) and a cysteine-proteinase inhibitor, potato multicystatin (PMC), as well as an increase in the activities of 84-, 95-, and 125-kD proteinases. Highly active, additional proteinases (75, 90, and 100 kD) appeared in the oldest tubers. Over 90% of the total proteolytic activity in aged tubers was sensitive to trans-epoxysuccinyl-L-leucylamido (4-guanidino) butane or leupeptin, whereas pepstatin was the most effective inhibitor of proteinases in young tubers. Proteinases in aged tubers were also inhibited by crude extracts or purified PMC from young tubers, suggesting that the loss of PMC was responsible for the age-induced increase in proteinase activity. Nonenzymatic oxidation, glycation, and deamidation of proteins were enhanced by aging. Aged tubers developed "daughter" tubers that contained 3-fold more protein than "mother" tubers, with a polypeptide profile consistent with that of young tubers. Although PMC and patatin were absent from the older mother tubers, both proteins were expressed in the daughter tubers, indicating that aging did not compromise the efficacy of genes encoding PMC and patatin. Unlike the mother tubers, proteinase activity in daughter tubers was undetectable. Our results indicate that tuber aging nonenzymatically modifies proteins, which enhances their susceptibility to breakdown; we also identify a role for PMC in regulating protein turnover in potato tubers.

show abstract

Section: Age-induced Nonenzymatic Modifications Of Tuber Proteinscontrasting

confidence: 54%

Section: Pcmt Activitymentioning

confidence: 99%

Age-Induced Protein Modifications and Increased Proteolysis in Potato Seed-Tubers1

1999

View full text Add to dashboard Cite

show abstract

“…3b and data not shown). Hence, in the gel image depicted for AdoMet-containing biopans after round 3, 6 of 18 amplicons were of the same size and sequence (lanes 5,6,7,9,16,17).…”

Section: Resultsmentioning

confidence: 99%

Substrates of the Arabidopsis thaliana Protein Isoaspartyl Methyltransferase 1 Identified Using Phage Display and Biopanning

Chen

Nayak

Majee

et al. 2010

Journal of Biological Chemistry

View full text Add to dashboard Cite

The role of protein isoaspartyl methyltransferase (PIMT) in repairing a wide assortment of damaged proteins in a host of organisms has been inferred from the affinity of the enzyme for isoaspartyl residues in a plethora of amino acid contexts. The identification of PIMT target proteins in plant seeds, where the enzyme is highly active and proteome long-lived, has been hindered by large amounts of isoaspartate-containing storage proteins. Mature seed phage display libraries circumvented this problem. Inclusion of the PIMT co-substrate, S-adenosylmethionine (AdoMet), during panning permitted PIMT to retain aged phage in greater numbers than controls lacking co-substrate or when PIMT protein binding was poisoned with S-adenosyl homocysteine. After four rounds, phage titer plateaued in AdoMet-containing pans, whereas titer declined in both controls. This strategy identified 17 in-frame PIMT target proteins, including a cupin-family protein similar to those identified previously using on-blot methylation. All recovered phage had at least one susceptible Asp or Asn residue. Five targets were recovered independently. Two in-frame targets were produced in Escherichia coli as recombinant proteins and shown by onblot methylation to acquire isoAsp, becoming a PIMT target. Both gained isoAsp rapidly in solution upon thermal insult. Mutant analysis of plants deficient in any of three in-frame PIMT targets resulted in demonstrable phenotypes. An overrepresentation of clones encoding proteins involved in protein production suggests that the translational apparatus comprises a subgroup for which PIMT-mediated repair is vital for orthodox seed longevity. Impaired PIMT activity would hinder protein function in these targets, possibly resulting in poor seed performance.

show abstract

“…1997Visick et al, 1998b;Yamamoto et al, 1998;Chavous et al, 2001;reviewed in Clarke, 2003). In plants, PIMT activity is thought to be involved in response to abiotic stress (Mudgett and Clarke, 1994;Kester et al, 1997;Mudgett et al, 1997;Thapar et al, 2001;Xu et al, 2004), but its role remains to be clearly established, especially in seeds. In this work, we have isolated Arabidopsis mutant lines exhibiting varying levels of PIMT and investigated the consequences of such a genetic modulation on several seed characteristics, including isoAsp accumulation in proteins, seed longevity, and seedling establishment under salt or osmotic stressful conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Also, a low vigor 17-year-old barley (Hordeum vulgare cv Himalaya) seedlot was shown to contain both a high isoAsp amount and a very low PIMT enzyme activity (Mudgett et al, 1997). These data raised the hypothesis that protein damage is particularly detrimental for seed longevity and correlatively that a limitation of isoAsp accumulation in the seed proteome contributes to seed vigor and longevity (Mudgett and Clarke, 1993;Kester et al, 1997;Mudgett et al, 1997). Consistent with this, aged barley seeds were shown to contain increased levels of isoAsp residues in proteins (Mudgett et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Protein Repairl-Isoaspartyl Methyltransferase1 Is Involved in Both Seed Longevity and Germination Vigor inArabidopsis

et al. 2008

View full text Add to dashboard Cite

The formation of abnormal amino acid residues is a major source of spontaneous age-related protein damage in cells. The protein L-isoaspartyl methyltransferase (PIMT) combats protein misfolding resulting from L-isoaspartyl formation by catalyzing the conversion of abnormal L-isoaspartyl residues to their normal L-aspartyl forms. In this way, the PIMT repair enzyme system contributes to longevity and survival in bacterial and animal kingdoms. Despite the discovery of PIMT activity in plants two decades ago, the role of this enzyme during plant stress adaptation and in seed longevity remains undefined. In this work, we have isolated Arabidopsis thaliana lines exhibiting altered expression of PIMT1, one of the two genes encoding the PIMT enzyme in Arabidopsis. PIMT1 overaccumulation reduced the accumulation of L-isoaspartyl residues in seed proteins and increased both seed longevity and germination vigor. Conversely, reduced PIMT1 accumulation was associated with an increase in the accumulation of L-isoaspartyl residues in the proteome of freshly harvested dry mature seeds, thus leading to heightened sensitivity to aging treatments and loss of seed vigor under stressful germination conditions. These data implicate PIMT1 as a major endogenous factor that limits abnormal L-isoaspartyl accumulation in seed proteins, thereby improving seed traits such as longevity and vigor. The PIMT repair pathway likely works in concert with other anti-aging pathways to actively eliminate deleterious protein products, thus enabling successful seedling establishment and strengthening plant proliferation in natural environments.

show abstract

Priming and accelerated ageing affect L-isoaspartyl methyltransferase activity in tomato (Lycopersicon esculentumMill.) seed

Cited by 30 publications

References 28 publications

Age-Induced Protein Modifications and Increased Proteolysis in Potato Seed-Tubers1

Age-Induced Protein Modifications and Increased Proteolysis in Potato Seed-Tubers1

Substrates of the Arabidopsis thaliana Protein Isoaspartyl Methyltransferase 1 Identified Using Phage Display and Biopanning

Protein Repairl-Isoaspartyl Methyltransferase1 Is Involved in Both Seed Longevity and Germination Vigor inArabidopsis

Contact Info

Product

Resources

About