Human DnaJ homologs dj2 and dj3, and bag-1 are positive cochaperones of hsc70
Human DnaJ homologs dj2 and dj3, and bag-1 are positive cochaperones of hsc70
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DOI：
10.1074/jbc.m002021200
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发表时间：
2000-08-11
影响因子：
4.8
通讯作者：
Mori, M
中科院分区：
文献类型：
--
作者：
Terada, K;Mori, M
DnaJ是哺乳动物热休克同源70（hsc 70）蛋白的重要辅伴侣。我们以前发现dj 2（HSDJ/hdj-2/rdj 1），而不是dj 1（hsp 40/hdj-1），是基于hsc 70的伴侣系统的伴侣DnaJ。在这里，我们比较了dj 1，dj 2和新发现的dj 3（cpr 3/DNJ 3/HIRIP 4/rdj 2）在培养细胞中的分布。dj 3和dj 2都是法尼基化的，并且普遍表达。在免疫细胞化学和亚组化研究中，这两种蛋白在正常条件下与hsc 70共定位，而热休克后dj 1和hsc 70明显共定位于核仁中。同时去除兔网织红细胞裂解物中的dj 2和dj 3显著降低了前鸟氨酸转氨甲酰酶的线粒体输入和胍变性荧光素酶的重折叠。再加入dj 2或dj 3导致这些反应的恢复。在重组系统中，hsc 70-dj 2和hsc 70-dj 3都能有效地进行蛋白质重折叠。抗凋亡蛋白袋-1进一步刺激ATP水解和蛋白质重折叠的两对。因此，dj 2和dj 3是细胞内hsc 70的伴侣DnaJ，功能上类似于dj 1并且比dj 1有效得多，并且bag-1是hsc 70-dj 2和hsc 70-dj 3系统的阳性共染色体。
DnaJ is an essential cochaperone of mammalian heat shock cognate 70 (hsc70) protein. We previously found that dj2 (HSDJ/hdj-2/rdj1), rather than dj1 (hsp40/hdj-1), is a partner DnaJ for the hsc70-based chaperone system. Here, we compared the distribution of dj1, dj2, and the newly found dj3 (cpr3/DNJ3/HIRIP4/rdj2) in cultured cells. Both dj3 as well as dj2 were farnesylated and were ubiquitously expressed. In immunocytochemical and subfractionation studies, these two proteins colocalized with hsc70 under normal conditions, However, dj1 and hsc70 apparently colocalized in the nucleoli after heat shock. Simultaneous depletion of dj2 and dj3 from rabbit reticulocyte lysate markedly reduced mitochondrial import of pre-ornithine transcarbamylase and refolding of guanidine-denatured luciferase. Re-addition of either dj2 or dj3 led to recovery of these reactions. In a reconstituted system, both hsc70-dj2 and hsc70-dj3 were effective in protein refolding. Anti-apoptotic protein bag-1 further stimulated ATP hydrolysis and protein refolding by both pairs. Thus, dj2 and dj3 are the partner DnaJs of hsc70 within the cell, functionally similar and much more efficient than dj1, and bag-1 is a positive cochapcrone of the hsc70-dj2 and hsc70-dj3 systems.