Protection from oxidative inactivation of the 20 S proteasome by heat-shock protein 90
Protection from oxidative inactivation of the 20 S proteasome by heat-shock protein 90
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DOI：
10.1042/bj3330407
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发表时间：
1998-07-15
影响因子：
4.1
通讯作者：
Friguet, B
中科院分区：
文献类型：
--
作者：
Conconi, M;Petropoulos, I;Friguet, B
热休克蛋白90（Hsp 90）参与了抗氧化失活和抑制多催化蛋白酶（MCP，也称为20 S蛋白酶体）。我们在这里报告，热休克蛋白90的保护和抑制作用取决于蛋白酶体的激活状态。当大鼠肝MCP处于其潜伏形式时，Hsp 90（以及α-晶状体蛋白）抑制N-Cbz-Leu-Leu-Leu-MCA-水解活性（Cbz =苄氧羰基; MCA = 7-氨基-4-甲基香豆素），但当MCP处于其活性形式时，未观察到抑制作用。活性MCP的金属催化氧化使Ala-Ala-Phe-MCA-水解（胰凝乳蛋白酶样）、N-Boc-Leu-Ser-Thr-Arg-MCA-水解（胰蛋白酶样; Boc =叔丁氧基羰基）、N-Cbz-Leu-Leu-Glu-β-萘胺水解（肽基谷氨酰-肽水解酶）和N-Cbz-Leu-Leu-Leu-MCA-水解活性失活，而当MCP处于其潜伏形式时，这些活性实际上增加。Hsp 90保护MCP活性形式的胰蛋白酶样和N-Cbz-Leu-Leu-Leu-MCA水解活性免受氧化失活，α-晶状体蛋白保护胰蛋白酶样活性。Hsp 90介导的保护的特异性进行了评估，通过定量分析的MCP亚基的氧化前后的MCP亚基的二维电泳图案，在存在或不存在的Hsp 90。发现用铁和抗坏血酸盐处理FAO肝癌细胞系可抑制MCP。通过用铁挑战细胞获得的Hsp 90过表达与MCP胰蛋白酶样活性对氧化失活的敏感性降低相关。耗尽的热休克蛋白90通过使用反义寡核苷酸导致MCP胰蛋白酶样活性的氧化失活的敏感性增加，提供证据的生理相关性的热休克蛋白90介导的保护MCP。
Heat-shock protein 90 (Hsp 90) has been implicated in both protection against oxidative inactivation and inhibition of the multicatalytic proteinase (MCP, also known as 20 S proteasome). We report here that the protective and inhibitory effects of Hsp 90 depend on the activation state of the proteasome. Hsp 90 (and also alpha-crystallin) inhibits the N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activity (Cbz = benzyloxycarbonyl; MCA = 7-amido-4-methylcoumarin) when the rat liver MCP is in its latent form, but no inhibitory effects are observed when the MCP is in its active form. Metal-catalysed oxidation of the active MCP inactivates the Ala-Ala-Phe-MCA-hydrolysing (chymotrypsin-like), N-Boc-Leu-Ser-Thr-Arg-MCA-hydrolysing (trypsin-like; Boc = t-butyloxycarbonyl), N-Cbz-Leu-Leu-Glu-beta-naphthylaminehydrolysing (peptidylglutamyl-peptide hydrolase) and N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activities, whereas these activities are actually increased when the MCP is in its latent form. Hsp 90 protects against oxidative inactivation of the trypsin-like and N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activities of the MCP active form, and alpha-crystallin protects the trypsin-like activity. The specificity of the Hsp 90-mediated protection was assessed by a quantitative analysis of the two-dimensional electrophoretic pattern of MCP subunits before and after oxidation of the MCP, in the presence or absence of Hsp 90. Treatment of the FAO hepatoma cell line with iron and ascorbate was found to inactivate the MCP. Hsp 90 overexpression obtained by challenging the cells with iron was associated with a decreased susceptibility to oxidative inactivation of the MCP trypsin-like activity. Depletion of Hsp 90 by using antisense oligonucleotides resulted in an increased susceptibility to oxidative inactivation of the MCP trypsin-like activity, providing evidence for the physiological relevance of Hsp 90-mediated protection of the MCP.