Related Experiment Video
Updated: Jun 27, 2026

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay
Published on: July 21, 2021
Nuclear localization mechanism of Hsp105beta and its possible function in mammalian cells
Youhei Saito1, Nobuyuki Yamagishi, Takumi Hatayama
1Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
Abstract:
Hsp105alpha and Hsp105beta are mammalian stress proteins of the Hsp105/110 family. We have shown that Hsp105beta localizes to the nucleus, whereas Hsp105alpha localizes to the cytoplasm of mammalian cells. Hsp105alpha localizes in the cytoplasm, as the nuclear export signal (NES) activity rather than nuclear localization signal (NLS) activity dominates in Hsp105alpha, due to suppression of the NLS activity. In this study, we determined the mechanisms behind the nuclear localization of Hsp105beta, and revealed that the NES was suppressed by the N-terminal (amino acids 3-10) or C-terminal (amino acids 699-756) region of Hsp105beta, and the NLS activity rather than NES activity seemed to dominate in Hsp105beta. Furthermore, as Hsp105beta which localizes in the nucleus, functioned as an inducer of Hsp70 in mammalian cells, Hsp105 family proteins may play an important role in the protection of cells against deleterious stressor together with Hsp70.
Related Concept Videos
Nuclear Protein Sorting
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Regulation of Nuclear Protein Sorting
Nuclear Localization Signals and Import
Nuclear Export
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Regulated mRNA Transport
Post-translational Translocation of Proteins to the RER
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...

