Oh, F. | Search bioRxiv

bioRxiv2023

Early-life stress triggers long-lasting organismal resilience and longevity via tetraspanin

Early-life stress experiences can produce lasting impacts on organismal adaptation and fitness. How transient stress elicits memory-like physiological effects is largely unknown. Here we show that early-life thermal stress strongly up-regulates tsp-1, a gene encoding the conserved transmembrane tetraspanin in C. elegans. TSP-1 forms prominent multimers and stable web- like structures critical for membrane barrier functions in adults and during aging. The up- regulation of TSP-1 persists even after transient early-life stress. Such regulation requires CBP- 1, a histone acetyl-transferase that facilitates initial tsp-1 transcription. Tetraspanin webs form regular membrane structures and mediate resilience-promoting effects of early-life thermal stress. Gain-of-function TSP-1 confers marked C. elegans longevity extension and thermal resilience in human cells. Together, our results reveal a cellular mechanism by which early-life thermal stress produces long-lasting memory-like impact on organismal resilience and longevity. TeaserStudies reveal mechanisms of how early-life heat exposure produces long-lasting benefits on longevity in the nematode C. elegans.

physiology↗

bioRxiv2022

A megaprotein-based molecular bridge critical for lipid trafficking and cold resilience

Cells adapt to cold by increasing levels of unsaturated phospholipids and membrane fluidity through homeostatic mechanisms conserved in nearly all forms of life. As most eukaryotic enzymes for lipid synthesis and desaturation localize on endoplasmic reticulum (ER) membranes, it remains unknown how ER-resident lipids rapidly distribute to plasma membranes (PM). Here we report an exceptionally large and evolutionarily conserved protein LPD-3 in C. elegans that plays critical roles in lipid trafficking and cold resilience. We identified lpd-3 mutants in a mutagenesis screen for genetic suppressors of the lipid desaturase FAT-7, and found that the 452 kDa megaprotein LPD-3 bridges ER and PM, consisting of a structurally predicted hydrophobic tunnel for lipid trafficking. Loss of LPD-3 caused abnormal cellular distribution of phospholipids, diminished FAT-7 abundance, and organismic vulnerability to cold. These phenotypic defects of lpd-3 mutants were rescued by Lecithin comprising unsaturated phospholipids. Importantly, we found that deficient lpd-3 homologues in Zebrafish and mammalian cells led to defects similar to those observed in C. elegans. As mutations in KIAA1109/BLTP1, the human orthologue of lpd-3, cause Alkuraya-Kucinskas syndrome, we propose that the LPD-3 family proteins may serve as evolutionarily conserved "highway bridges" critical for ER-associated non-vesicular trafficking of lipids and resilience to cold stress in eukaryotic cells.

cell biology↗