Park H S, Lee J S, Huh S H, Seo J S, Choi E J
National Creative Research Initiative Center for Cell Death, Graduate School of Biotechnology, Korea University, Seoul 136-701 Korea.
EMBO J. 2001 Feb 1;20(3):446-56. doi: 10.1093/emboj/20.3.446.
Hsp72, a major inducible member of the heat shock protein family, can protect cells against many cellular stresses including heat shock. In our present study, we observed that pretreatment of NIH 3T3 cells with mild heat shock (43 degrees C for 20 min) suppressed UV-stimulated c-Jun N-terminal kinase 1 (JNK1) activity. Constitutively overexpressed Hsp72 also inhibited JNK1 activation in NIH 3T3 cells, whereas it did not affect either SEK1 or MEKK1 activity. Both in vitro binding and kinase studies indicated that Hsp72 bound to JNK1 and that the peptide binding domain of Hsp72 was important to the binding and inhibition of JNK1. In vivo binding between endogenous Hsp72 and JNK1 in NIH 3T3 cells was confirmed by co-immunoprecipitation. Hsp72 also inhibited JNK-dependent apoptosis. Hsp72 antisense oligonucleotides blocked Hsp72 production in NIH 3T3 cells in response to mild heat shock and concomitantly abolished the suppressive effect of mild heat shock on UV-induced JNK activation and apoptosis. Collectively, our data suggest strongly that Hsp72 can modulate stress-activated signaling by directly inhibiting JNK.
热休克蛋白72（Hsp72）是热休克蛋白家族中一种主要的可诱导成员，能够保护细胞抵御包括热休克在内的多种细胞应激。在我们目前的研究中，我们观察到用温和热休克（43℃，20分钟）预处理NIH 3T3细胞可抑制紫外线刺激的c-Jun氨基末端激酶1（JNK1）活性。组成型过表达的Hsp72也能抑制NIH 3T3细胞中的JNK1激活，而对SEK1或MEKK1活性没有影响。体外结合和激酶研究均表明Hsp72与JNK1结合，且Hsp72的肽结合结构域对于JNK1的结合和抑制很重要。通过共免疫沉淀证实了NIH 3T3细胞中内源性Hsp72与JNK1之间的体内结合。Hsp72还能抑制JNK依赖性凋亡。Hsp72反义寡核苷酸可阻断NIH 3T3细胞在温和热休克刺激下产生Hsp72，并同时消除温和热休克对紫外线诱导的JNK激活和凋亡的抑制作用。总体而言，我们的数据强烈表明Hsp72可通过直接抑制JNK来调节应激激活信号。
