Rincon Paz, M. | bioRxiv Science

bioRxiv2026

Regulation of Mechanosensor PIEZO Channel Trafficking in C. elegans Germline

PIEZO proteins are essential mechanotransductive ion channels, yet mechanisms governing their subcellular localization and membrane trafficking remain elusive. Here, we leverage the C. elegans germline as an in vivo imaging platform to decipher the molecular networks directing PIEZO channel dynamics. High-resolution confocal imaging of endogenously tagged PEZO-1, the C. elegans ortholog, reveals that PEZO-1 compartmentalizes with caveolae protein CAV-1 and the recycling endosome regulator RAB-11. Depletion of rab-11 or the t-SNARE syx-4 severely impairs the translocation of PEZO-1-positive vesicles to the plasma membrane, establishing a reliance on conserved, RAB-11-dependent machinery. Furthermore, we demonstrated that PEZO-1 structural integration is essential for vesicle formation and transport; truncating either the N-terminal transmembrane domains or the C-terminal ion pore induces aberrant vesicle morphology and arrests trafficking. Crucially, PEZO-1 vesicle formation and transport are non-autonomously modulated by reproductive signals requiring male sperm or major sperm protein (MSP) signaling. Finally, introducing conserved disease-associated pathogenic PIEZO mutations markedly suppresses its cytosolic and plasma membrane expression. Collectively, our findings define a fundamental cytological framework regulating PIEZO channel dynamics, shedding light on the molecular etiology of PIEZO-associated channelopathies.

genetics↗

bioRxiv2026

Genetic Compensation Restores Embryonic Viability in Fatty Acid Synthase Mutants

Fatty acid synthase (FASN) is a key rate-limited, dimeric multi-enzyme complex in the de novo lipogenesis pathway. Each FASN monomer contains seven catalytic domains, which coordinate the stepwise conversion of acetyl-CoA into fatty acids. While FASN has been extensively studied in cultured cells, particularly for its oncogenic role, its functions in the germline and early embryonic development remain elusive. A major challenge is that the FASN dysfunction typically causes embryonic lethality in animal models, which complicates detailed functional analysis and the identification of compensatory genetic interactors during development. To overcome this limitation and identify novel genetic suppressors of the FASN gene, we utilized a temperature-sensitive allele, fasn-1(g43ts) (A1424T), in the genetically tractable model Caenorhabditis elegans, to conduct unbiased forward genetic screens. We isolated 22 suppressor lines that significantly restored embryonic viability in the fasn-1(g43ts) mutant at the non-permissive temperature. Using a combination of MIP-MAP genomic mapping and a customized bioinformatic pipeline, we identified six missense mutations in the ptr-6 gene, which encodes a protein containing a patched domain associated with the Hedgehog signaling pathway. To validate this genetic suppression, we recreated one of the loss-of-function mutations, ptr-6 (W701*), in the fasn-1(g43ts) background using CRISPR/Cas9 gene editing. Notably, ptr-6(W701*) robustly rescued the embryonic lethality and permeability defects caused by fasn-1 loss-of-function. Taken together, our findings expand the genetic regulatory network of fatty acid synthase during early embryogenesis and highlight ptr-6 and Hedgehog signaling pathway as potential genetic modifiers of FASN-associated developmental and metabolic disorders.

genetics↗