Ugalde MV, Alecki C, Rizwan J, Le P, Jacob-Tomas S, Xu JM, Minotti S, Wu T, Durham H, Yeo G. Localized molecular chaperone synthesis maintains neuronal dendrite proteostasis.
RESEARCH SQUARE 2023:rs.3.rs-3673702. [PMID:
38168440 PMCID:
PMC10760236 DOI:
10.21203/rs.3.rs-3673702/v1]
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Abstract
Proteostasis is maintained through regulated protein synthesis and degradation and chaperone-assisted protein folding. However, this is challenging in neuronal projections because of their polarized morphology and constant synaptic proteome remodeling. Using high-resolution fluorescence microscopy, we discovered that neurons localize a subset of chaperone mRNAs to their dendrites and use microtubule-based transport to increase this asymmetric localization following proteotoxic stress. The most abundant dendritic chaperone mRNA encodes a constitutive heat shock protein 70 family member (HSPA8). Proteotoxic stress also enhanced HSPA8 mRNA translation efficiency in dendrites. Stress-mediated HSPA8 mRNA localization to the dendrites was impaired by depleting fused in sarcoma-an amyotrophic lateral sclerosis-related protein-in cultured mouse motor neurons and expressing a pathogenic variant of heterogenous nuclear ribonucleoprotein A2/B1 in neurons derived from human induced pluripotent stem cells. These results reveal a crucial and unexpected neuronal stress response in which RNA-binding proteins increase the dendritic localization of HSPA8 mRNA to maintain proteostasis and prevent neurodegeneration.
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