- Wang, Changnan;
- Wang, Bingying;
- Pandey, Taruna;
- Long, Yong;
- Zhang, Jianxiu;
- Oh, Fiona;
- Sima, Jessica;
- Guo, Ruyin;
- Liu, Yun;
- Zhang, Chao;
- Mukherjee, Shaeri;
- Bassik, Michael;
- Lin, Weichun;
- Deng, Huichao;
- Vale, Goncalo;
- McDonald, Jeffrey G;
- Shen, Kang;
- Ma, Dengke K
Cells adapt to cold by increasing levels of unsaturated phospholipids and membrane fluidity through conserved homeostatic mechanisms. Here we report an exceptionally large and evolutionarily conserved protein LPD-3 in C. elegans that mediates lipid trafficking to confer cold resilience. We identify lpd-3 mutants in a mutagenesis screen for genetic suppressors of the lipid desaturase FAT-7. LPD-3 bridges the endoplasmic reticulum (ER) and plasma membranes (PM), forming a structurally predicted hydrophobic tunnel for lipid trafficking. lpd-3 mutants exhibit abnormal phospholipid distribution, diminished FAT-7 abundance, organismic vulnerability to cold, and are rescued by Lecithin comprising unsaturated phospholipids. Deficient lpd-3 homologues in Zebrafish and mammalian cells cause defects similar to those observed in C. elegans. As mutations in BLTP1, the human orthologue of lpd-3, cause Alkuraya-Kucinskas syndrome, LPD-3 family proteins may serve as evolutionarily conserved highway bridges critical for ER-associated non-vesicular lipid trafficking and resilience to cold stress in eukaryotic cells.