Functional characterisation of PREL-1 and PREL-3 proteins as putative intramitochondrial phospholipid transporters governing homeostasis and organismal health in Caenorhabditis elegans.

INTRODUCTION: Mitochondrial phospholipids are crucial for maintaining structure and function; however, their roles and transport pathways are not fully understood in a multicellular model organism. In this study, we examined two putative Caenorhabditis elegans proteins, B0334.4 (PREL-1) and F15D3.6 (PREL-3), thought to be involved in intramitochondrial phospholipid transport. METHODS: In-silico molecular docking analysis was performed to predict phospholipid binding specificity of PREL-1 and PREL-3. RNA interference (RNAi) was used to knockdown the expression of these proteins in C. elegans. Upon knockdown, development, lifespan, reproduction, locomotion, stress response, and mitochondrial phospholipid composition were analysed. RESULTS: Docking studies predicted that phosphatidic acid (PA) preferentially binds to PREL-1 compared to PREL-3. Mitochondrial profiling revealed loss of mitochondrial phospholipid homeostasis upon RNAi knockdown. This resulted in mitochondrial dysfunction leading to impaired reproduction, respiration, locomotion, and elevated ROS levels in worms lacking these phospholipid transporters. CONCLUSION: Our findings support the role of PREL-1 and PREL-3 proteins in mitochondrial phospholipid homeostasis and suggest their function as PRELI- family phospholipid transporters. This study demonstrates the importance of these phospholipid transporters in mitochondrial function, growth, lifespan, and organism physiology.