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Family of Hsp70 Molecular Chaperones and Their Regulators

Hsp70 분자 샤페론과 조절인자

  • Published : 2007.12.30

Abstract

Proteins are involved in promoting or controlling virtually every event on which our lives depend. Proteins are synthesized in cytosol and in the endoplasmic reticulum where their synthesis machinery are tightly controlled. However, not all of newly synthesized proteins are survived and conduct their essential functions to maintain cell's lives. It was reported that one-third of synthesized proteins are rapidly destroyed by proteasome under the most physiological conditions. full-length translated proteins, which survived, must undergo proper folding and assemble process. Some proteins are spontaneously folded while others require molecular chaperones and folding enzymes to be properly folded. Molecular chaperones are ubiquitously present within the subcellular organelles and from bacteria to animals and plants. Among those members of Hsp70 family have been extensively studied and their regulators have been discovered in the last decade. Here, a brief overview is presented for functional mechanism of Hsp70 homologues and the roles of their regulators. Since biological function of Hsp70 family other than chaperonic function are expending the review would give basic understanding of partnership between Hsp70 family and their regulators.

생명체 내에서 일어나는 거의 모든 반응은 단백질이 촉진하거나 수행한다. 단백질은 세포질과 소포체에서 합성될 때 엄격하게 조절된다. 그러나, 새로이 합성된 모든 단백질이 살아남아서 생명을 유지시키는 기능에 관여하게 되지는 않는다. 가장 알맞은 생리학적 in vitro 실험 조건에서 새로이 합성된 단백질의 약 3분의 1 정도는 합성되자마자 proteasome에 의해 빠르게 분해된다고 보고되었다. 또한, 단백질은 합성이 성공적으로 이루어진 이후에는 3차원 구조를 갖기 위해 접힘(folding)이 이루어져야 하고, subunit들은 assembly 과정을 거쳐야 비로소 성숙된 단백질로서 기능을 하게 된다. 어떤 단백질군은 자연적으로 접힘이 일어나는 반면 어떤 단백질군은 분자 샤페론(molecular chaperones)과 folding enzymes의 도움을 받아야만 접힘이 일어난다. 분자 샤페론은 세포 전역에 분포하고 있으며, 세균에서부터 고등 동식물에 이르기까지 모든 생명체에 존재한다. 이들 중 Hsp70군은 많이 연구된 분자 샤페론으로서 지난 10여년 동안 조절인자들이 새로이 발견되어 작용 mechanism이 보다 자세히 밝혀졌다. 본 총설에서 Hsp70군과 그 조절인자들에 대한 전반적인 서술을 하였으며, 이들의 기능이 분자 샤페론 기능 외에 생체 내에서 중요한 기능들이 새롭게 밝혀지고 있어 이들의 작용 mechanism을 조명함으로 이해를 돕고자 한다.

Keywords

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