A Novel Mechanism for Small Heat Shock Proteins to Function as Molecular Chaperones

نویسندگان

  • Kaiming Zhang
  • Anastasia N. Ezemaduka
  • Zhao Wang
  • Hongli Hu
  • Xiaodong Shi
  • Chuang Liu
  • Xinping Lu
  • Xinmiao Fu
  • Zengyi Chang
  • Chang-Cheng Yin
چکیده

Small heat shock proteins (sHSPs) are molecular chaperones ubiquitously present in all forms of life, but their function mechanisms remain controversial. Here we show by cryo-electron microscopy and single particle 3D reconstruction that, at the low temperatures (4-25°C), CeHSP17 (a sHSP from Caenorhabditis elegans) exists as a 24-subunit spherical oligomer with tetrahedral symmetry. Our studies demonstrate that CeHSP17 forms large sheet-like super-molecular assemblies (SMAs) at the high temperatures (45-60°C), and such SMAs are apparently the form that exhibits chaperone-like activity. Our findings suggest a novel molecular mechanism for sHSPs to function as molecular chaperones.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

HDAC Inhibitors and Heat Shock Proteins (Hsps)

Epigenetic alterations, including DNA acetylation, hypermethylation and hypomethylation, and the associated transcriptional changes of the affected genes are central to the evolution and progression of various human cancers, including pancreatic cancer. Cancer-associated epigenetic alterations are attractive therapeutic targets because such epigenetic alterations, unlike genetic changes, are po...

متن کامل

Chaperone function and mechanism of small heat-shock proteins.

Small heat-shock proteins (sHSPs) are ubiquitous ATP-independent molecular chaperones that play crucial roles in protein quality control in cells. They are able to prevent the aggregation and/or inactivation of various non-native substrate proteins and assist the refolding of these substrates independently or under the help of other ATP-dependent chaperones. Substrate recognition and binding by...

متن کامل

Molecular chaperones and the cytoskeleton.

Heat shock proteins, first observed because they are preferentially synthesized by organisms exposed to heat or other physiological stress, are also synthesized constitutively. These proteins are divided into several families, namely, HSP100, 90, 70, 60 (chaperonin), and the small heat shock/alpha-crystallin proteins. They enjoy a wide phylogenetic distribution and are important because they fu...

متن کامل

Oligomers of Heat-Shock Proteins: Structures That Don't Imply Function

Most proteins must remain soluble in the cytosol in order to perform their biological functions. To protect against undesired protein aggregation, living cells maintain a population of molecular chaperones that ensure the solubility of the proteome. Here we report simulations of a lattice model of interacting proteins to understand how low concentrations of passive molecular chaperones, such as...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 5  شماره 

صفحات  -

تاریخ انتشار 2015