Kumar, A.; Sanders, M.; Zhang, H.; Zhou, L.; Parveen, S.; Kelly, C. V.; Granneman, J. G.; Huang, Y.-m.

ABHD5 plays a critical role in lipid metabolism, regulating fatty acid mobilization, skin barrier formation, and phospholipid remodeling. ABHD5 lacks catalytic activity and instead functions as an essential co-regulator of PNPLA enzymes. Understanding how ABHD5 interacts with lipid droplet (LD) and endoplasmic reticulum (ER) membranes is crucial for unraveling its regulatory role in lipid metabolism and identifying potential therapeutic targets for metabolic diseases. While previous studies have modeled ABHD5 structure in solution, its function relies on membrane interactions, requiring a detailed investigation of its binding mechanisms. In this study, we employed multiscale simulations with experimental validation to reveal how ABHD5 interacts with ER and LD. Our findings show that ABHD5 binds membranes through its N-terminus and insertion segment, which subsequently triggers structural changes in the pseudosubstrate pocket and alters lipid distribution. This study also identifies key residues essential for membrane binding, providing potential targets for developing lipid metabolism modulators. These results uncover a previously unrecognized mechanism by which ABHD5 interacts with membranes, offering new insights into lipolysis regulation and potential therapeutic strategies for metabolic diseases.