The roles of a flagellar HSP40 ensuring rhythmic beating
| Autor: | Emiliya Poghosyan, Takashi Ishikawa, Lenka Rezabkova, Hitoshi Sakakibara, Pinfen Yang, Bridget Mehall, Ritsu Kamiya, Masafumi Hirono, Xiaoyan Zhu |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Transposable element
Models Molecular Donor cell Electron Microscope Tomography Axoneme Mutant Mutagenesis (molecular biology technique) Plasma protein binding Flagellum 03 medical and health sciences 0302 clinical medicine Bacterial Proteins Molecular Biology Gene 030304 developmental biology 0303 health sciences biology Chlamydomonas Cell Biology Articles HSP40 Heat-Shock Proteins biology.organism_classification Cell biology Cell Motility Mutagenesis Insertional Flagella Mutation DNA Transposable Elements 030217 neurology & neurosurgery Protein Binding |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| Popis: | HSP40s are regarded as cochaperones, perpetually shuttling client polypeptides to HSP70s for refolding. However, many HSP40s that are central for disparate processes diverge from this paradigm. To elucidate the noncanonical mechanisms, we investigated HSP40 in the radial spoke (RS) complex in flagella. Disruption of the gene by the MRC1 transposon in Chlamydomonas resulted in jerky flagella. Traditional electron microscopy, cryo-electron tomography, and sub-tomogram analysis revealed RSs of various altered morphologies that, unexpectedly, differed between the two RS species. This indicates that HSP40 locks the RS into a functionally rigid conformation, facilitating its interactions with the adjacent central pair apparatus for transducing locally varied mechanical feedback, which permits rhythmic beating. Missing HSP40, like missing RSs, could be restored in a tip-to-base direction when HSP40 mutants fused with a HSP40 donor cell. However, without concomitant de novo RS assembly, the repair was exceedingly slow, suggesting HSP40/RS-coupled intraflagellar trafficking and assembly. Biochemical analysis and modeling uncovered spoke HSP40’s cochaperone traits. On the basis of our data, we propose that HSP40 accompanies its client RS precursor when traveling to the flagellar tip. Upon arrival, both refold in concert to assemble into the mature configuration. HSP40’s roles in chaperoning and structural maintenance shed new light on its versatility and flagellar biology. |
| Databáze: | OpenAIRE |
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