Molecular chaperone HSP70 prevents formation of inclusion bodies of the 25-kDa C-terminal fragment of TDP-43 by preventing aggregate accumulation.

Molecular chaperone HSP70 prevents formation of inclusion bodies of the 25-kDa C-terminal fragment of TDP-43 by preventing aggregate accumulation.
Cell Stress Chaperones. 2018 Aug 11;:
Authors: Kitamura A, Iwasaki N, Kinjo M
Abstract
Transactive response DNA/RNA-binding protein 43-kDa (TDP-43) C-terminal fragments, such as a 25-kDa fragment (TDP-25), have been identified as a ubiquitinated and phosphorylated components of inclusion bodies (IBs) in motor neurons from amyotrophic lateral sclerosis patients. Cells contain proteins that function as molecular chaperones and prevent aggregate formation of misfolded and aggregation-prone proteins. Recently, we reported that heat shock protein (HSP)70, an abundant molecular chaperone, binds to TDP-25 in an ATP-dependent manner; however, whether HSP70 can prevent the formation of TDP-25-related IBs remains unknown. Here, we showed that HSP70 prevented TDP-25 aggregation according to green fluorescent protein-tagged TDP-25 (G-TDP-25) colocalization in the cytoplasm with mCherry-tagged HSP70 (HSP70-R). The mobile fraction of HSP70-R in the cytoplasmic IBs associated with G-TDP-25 increased relative to that of G-TDP-25, suggesting that HSP70 strongly bound to G-TDP-25 in the IBs, whereas a portion remained dissociated from the IBs. Importantly, the proportion of G-TDP-25 IBs was significantly decreased by HSP70-R overexpression; however, G-TDP-25 levels in the insoluble fraction remained unchang...

Source: Cell Stress and Chaperones - August 11, 2018 Category: Cytology Authors: Kitamura A, Iwasaki N, Kinjo M Tags: Cell Stress Chaperones Source Type: research