1Aix Marseille Univ, CNRS, BIP UMR 7281, IMM, 31 Chemin Joseph Aiguier, 13402 Marseille, France.
2Protein Expression Facility, CNRS, IMM, 31 Chemin Joseph Aiguier, 13402 Marseille, France.
Commun Biol. 2019 Aug 29;2:323. doi: 10.1038/s42003-019-0567-3. eCollection 2019.
DnaK (Hsp70) is a major ATP-dependent chaperone that functions with two co-chaperones, a J-domain protein (JDP) and a nucleotide exchange factor to maintain proteostasis in most organisms. Here, we show that the environmental bacterium possesses a previously uncharacterized short JDP, AtcJ, dedicated to cold adaptation and composed of a functional J-domain and a C-terminal extension of 21 amino acids. We showed that is the first gene of an operon encoding also AtcA, AtcB and AtcC, three proteins of unknown functions. Interestingly, we found that the absence of AtcJ, AtcB or AtcC leads to a dramatically reduced growth at low temperature. In addition, we demonstrated that AtcJ interacts via its C-terminal extension with AtcC, and that AtcC binds to AtcB. Therefore, we identified a previously uncharacterized protein network that involves the DnaK system with a dedicated JDP to allow bacteria to survive to cold environment.
DnaK（Hsp70）是一种主要的 ATP 依赖性伴侣蛋白，与两种共伴侣蛋白（J 结构域蛋白和核苷酸交换因子）一起发挥作用，以维持大多数生物体的蛋白质平衡。在这里，我们表明，环境细菌 拥有以前未被描述的短 J 结构域 AtcJ，专门用于适应寒冷，并由一个功能 J 结构域和 21 个氨基酸的 C 末端延伸组成。我们表明， 是一个操纵子的第一个基因，该操纵子还编码 AtcA、AtcB 和 AtcC，这三种蛋白的功能未知。有趣的是，我们发现 AtcJ、AtcB 或 AtcC 的缺失会导致细菌在低温下的生长明显减少。此外，我们证明 AtcJ 通过其 C 末端延伸与 AtcC 相互作用，并且 AtcC 与 AtcB 结合。因此，我们确定了一个以前未被描述的蛋白质网络，该网络涉及具有专用 JDP 的 DnaK 系统，以使细菌能够在寒冷环境中生存。
