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標題: | 過多糖類攝取會經由PKA調控來降低HSP90蛋白質摺疊活性 Glucose intake hampers PKA-regulated HSP90 chaperone activity |
作者: | Yu-Chen Chen 陳育辰 |
指導教授: | 鄧述諄(Shu-Chun Teng) |
關鍵字: | 蛋白質摺疊,蛋白質衡定,卡路里限制,分子伴侶蛋白, HSP90,calorie restriction,PKA,PP2C,proteostasis, |
出版年 : | 2019 |
學位: | 博士 |
摘要: | 老化是與生理功能逐漸喪失所造成相關的複雜現象,其中與老化相關的因子包括營養物質的感受與蛋白質穩定都會控制壽命的長短。雖然目前研究有許多方法鑑定控制長壽的候選基因,但是參與老化途徑的分子機制仍需要更深入的研究。在本研究中,我們使用了質譜儀定量分析技術進行篩選,並鑑定了酵母蛋白中受到卡路里限制時具有顯著改變的磷酸化/去磷酸化位點。針對其中135個蛋白進行功能性分析,發現Ids2在卡路里限制下會被PP2C去磷酸化並且活化,而相反的,在糖類過多的狀態下會被PKA而抑制其活性。在ids2以及模擬磷酸化ids2的細胞經測試顯示對熱的感受性增加以及壽命縮短。此外,Ids2可能作為HSP90 (Hsc82, Hsp82)的分子伴侶(co-chaperone)蛋白,會與之結合並形成複合物來增強蛋白摺疊活性,然而經磷酸化的Ids2會阻礙其與HSP90的結合。因此,細胞可藉由PP2C和PKA途徑因應糖類的多寡來調控蛋白質摺疊活性,使細胞能夠維持蛋白質的品質以及維持細胞的壽命。
在另一個與老化相關的層面,ATM與ATR在之前被認為是DNA受損關鍵性調控的激酶,然而在近期發現可能會影響造成蛋白質摺疊。所以在本研究中,我們測試ATM與ATR是否會藉由HSP90複合蛋白的調控機制來影響蛋白質的品質。結果顯示ATM與ATR的確會影響HSP90的活性,但詳細機制仍需更進一步的研究。 Aging is an intricate phenomenon associated with the gradual loss of physiological functions, and both nutrient sensing and proteostasis control lifespan. Although multiple approaches have facilitated the identification of candidate genes that govern longevity, the molecular mechanisms that link aging pathways are still elusive. Here, we conducted a quantitative mass spectrometry screen and identified all phosphorylation/dephosphorylation sites on yeast proteins that significantly responded to calorie restriction, a well-established approach to extend lifespan. Functional screening of 135 potential regulators uncovered that Ids2 is activated by PP2C under CR and inactivated by PKA under glucose intake. ids2or ids2 phosphomimetic cells displayed heat sensitivity and lifespan shortening. Ids2 serves as a co-chaperone to form a complex with Hsc82 or the redundant Hsp82, and phosphorylation impedes its association with chaperone HSP90. Thus, PP2C and PKA may orchestrate glucose sensing and protein folding to enable cells to maintain protein quality for sustained longevity. At another level associated with aging, ATM and ATR were previously thought to be key regulators of DNA damage but recently found to have an additional role in protein folding. We therefore tested whether ATM and ATR survey the quality of proteins via the regulatory mechanism of HSP90 chaperone complex. The results showed that ATM and ATR affect the activity of HSP90, but the detailed mechanism remains further study. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/73509 |
DOI: | 10.6342/NTU201900634 |
全文授權: | 有償授權 |
顯示於系所單位: | 微生物學科所 |
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