• 제목/요약/키워드: shock proteins

검색결과 371건 처리시간 0.052초

Functional switching of eukaryotic 2-Cys peroxiredoxins from peroxidases to molecular chaperones in response to oxidative stress

  • Jang, Ho-Hee;Lee, Sang-Yeol
    • 한국식물생명공학회:학술대회논문집
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    • 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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    • pp.40-64
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    • 2005

  • Much biochemical information on peroxiredoxins (Prxs) has been reported but a genuine physiological function for these proteins has not been established. We show here that two cytosolic yeast Prxs, cPrxI and II, exist in a variety of forms that differ in their structure and molecular weight (MW) and that they can act both as a peroxidase and as a molecular chaperone. The peroxidase function predominates in the lower MW proteins, whereas the chaperone function is more significant in the higher MW complexes. Oxidative stress and heat shock exposure of yeasts causesthe protein structures of cPrxI and II to shift from low MW species to high MW complexes. This triggers a peroxidase-to-chaperone functional switch. These in vivo changes are primarily guided by the active peroxidase site residue, $Cys^{47}$, which serves as an efficient $'H_2O_2-sensor'$ in the cells. The chaperone function of the proteins enhances yeast resistance to heat shock.

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Proline Analogs, L-Azetidine-2-Carboxylic Acid and 3,4-Dehydro-L-Proline, Induce Stress Response in Drosophila Kc Cells

  • Moon, Sung-Joon;Han, Ching-Tack
    • BMB Reports
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    • 제31권2호
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    • pp.201-208
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    • 1998

  • Amino acid analogs, like other inducers of stress response, induce the synthesis of stress proteins in mammalian cells. In this study, Drosophila Kc cells, in which translation is tightly controlled during stress response, was treated with proline analogs, L-azetidine-2-carboxylic acid (AzC) and 3,4-dehydro-L-proline (dh-P). Kc cells exposed to AzC or dh-P induced the synthesis of several proteins which had the same molecular weights as known heat shock proteins. However, in Kc cells, normal protein synthesis still continued in the presence of amino acids analogs unlike in heat-shocked cells. For the induction of stress response, the incorporation of dh-P into the protein was not essential, but the incorporation of AzC was. The stress protein synthesis was regulated mainly at the transcriptional level by AzC, whereas it was regulated by dh-P at the transcription level and possibly posttranscription level. During recovery, the stress protein synthesis stopped sooner in analog-treated cells than in heat-shocked cells even though the accumulated amount of Hsp70 was much less in proline analogstreated cells. It could be concluded that the proline analogs, AzC and dh-P, induced stress response through a different mechanism from heat shock.

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Salicylic Acid and Wounding Induce Defense-Related Proteins in Chinese Cabbage

  • Kim, Hong-Nam;Cha, Jae-Soon;Cho, Tae-Ju;Kim, Hak-Yong
    • Animal cells and systems
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    • 제7권3호
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    • pp.213-219
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    • 2003

  • The response of plants to pathogens and wounding is dependent upon very sensitive perception mechanisms. Although genetic approaches have revealed a variety of resistance genes that activate common defense responses, defense-related proteins are not well characterized in plants. Therefore, we used a proteomic approach to determine which defense-related proteins are induced by salicylic acid (SA) and wounding in Chinese cabbage. We found that SA and wounding induce pathogenesis-related protein 1a (PR1a) at both protein and mRNA levels using proteomics and Northern blot analysis, respectively. This indicates that our proteomic approach is useful for identifying defense-related proteins. We also identified several other proteins that are induced by SA or wounding. Among the seven SA-induced proteins identified, four may be defense-related, including defense-related protein, phospholipase D (PLD), resistance protein RPS2 homolog, and L-ascorbate peroxidase. Out of the six wounding-induced proteins identified, three may be defense-related: heat shock cognate protein 70 (HSC70), polygalacturonase, and peroxidase P7. The precise functions of these proteins in plant defense responses await further study. However, identification of the defense-related proteins described in this study should allow us to better understand the mechanisms and signal transduction pathways involved in defense responses in Chinese cabbage.

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열충격 Salmonella Typhimurium의 산과 산화제에서 생존력 증가 (Increased Viability of Sub-lethal Heat Shocked Salmonella Typhimurium on Acids and Oxidants)

  • 문보연;박종현
    • 한국식품과학회지
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    • 제40권6호
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    • pp.712-716
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    • 2008

  • Salmonella로부터 식품 안전성을 높이기 위한 보존법의 병용처리에 의한 효과를 평가하고자 S. Typhimurium을 열과 산, 산화제 등으로 연속 처리한 후 생균수를 측정하여 효과를 분석하였다. 그리고 열충격에 의하여 S. Typhimurium 내에 발현되거나 억제되는 단백질을 이차원 전기영동과 MALDI-TOF 질량분석기로 분석하였다. 열처리된 S. Typhimurium은 초산과 염산의 pH 4에서의 생균수가 1.3-1.8 log CFU/mL가 줄었고 비열처리 S. Typhimurium은 생균수가 약 5 log CFU/mL가 감소하였다. 열처리 S. Typhimurium은 butyl hydrogen peroxide와 과산화수소에서 생균수가 1.1-1.7 log CFU/mL가 줄었으나 비열처리 S. Typhimurium은 5.4-5.6 log CFU/mL 감소하였다. 충분하지 않은 사멸 열처리는 S. Typhimurium의 생존력을 증가시키고 산과 산화제 등의 보존제에서 저항성이 커지는 것을 알 수가 있었다. 이차원 전기영동과 MALDI-TOF 질량분석에 의한 발현 단백질 분석 결과 비열처리 S. Typhimurium은 17개의 단백질이 검출되었고 열처리 S. Typhimurium에는 13개의 단백질만 검출되었다. 이들 중에 열충격 단백질로 알려진 DnaK, small heat shock protein 등이 검출되었고 이들이 산과 산화제에서의 생존 저항성 증가와 관련이 있을 것으로 보인다. 그러므로 열처리를 포함하는 hurdle technology를 적용하여 식품을 보존처리할 때 다른 보존제에 대한 교차보호성이 증가되는 사실을 고려하여 적절한 열처리가 고려되어야 된다는 것을 알 수 있었다.

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