Neutral lipids regulate amphipathic helix affinity for model lipid droplets.

Aymeric Chorlay, Abdou Rachid Thiam

The Journal of cell biology 2020 Apr 06

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Cellular lipid droplets (LDs) have a neutral lipid core shielded from the aqueous environment by a phospholipid monolayer containing proteins. These proteins define the biological functions of LDs, and most of them bear amphipathic helices (AH), which can selectively target to LDs, or to LD subsets. How such binding preference happens remains poorly understood. Here, we found that artificial LDs made of different neutral lipids but presenting equal phospholipid packing densities differentially recruit AHs. Varying the phospholipid density shifts the binding levels, but the differential recruitment is unchanged. We found that the binding level of AHs is defined by their interaction preference with neutral lipids and ability to decrease surface tension. The phospholipid packing level regulates mainly the amount of neutral lipid accessible. Therefore, it is the hydrophobic nature of the phospholipid packing voids that controls the binding level of AHs. Our data bring us a major step closer to understanding the binding selectivity of AHs to lipid membranes. © 2020 Chorlay and Thiam.

Citation

Aymeric Chorlay, Abdou Rachid Thiam. Neutral lipids regulate amphipathic helix affinity for model lipid droplets. The Journal of cell biology. 2020 Apr 06;219(4)