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The roles of a flagellar HSP40 ensuring rhythmic beating
- Source :
- Molecular Biology of the Cell
- Publication Year :
- 2019
- Publisher :
- The American Society for Cell Biology, 2019.
-
Abstract
- 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.
- Subjects :
- 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
Subjects
Details
- Language :
- English
- ISSN :
- 19394586 and 10591524
- Volume :
- 30
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Molecular Biology of the Cell
- Accession number :
- edsair.doi.dedup.....ceabc633cd47da77d2b351776ef05b6c