抄録
The presence of a cis–double bond in phospholipid acyl chains is thought to be a determinant of bilayer membrane mechanics. However, it is unclear whether cell membrane deformation is controlled by the Δ9–desaturase–dependent production of monounsaturated fatty acids (MUFAs), which are single cis–double bond–containing fatty acids. In this study, we used Drosophila S2 cells, in which the MUFA content in phospholipid acyl chains could be selectively lowered without affecting cholesterol and polyunsaturated fatty acid levels, by inhibiting Δ9–desaturase DESAT1, the sole fatty acid desaturase in this cell line. Inhibition of DESAT1 decreased cellular deformability and caused a 2.0–fold increase in membrane tension. Notably, the DESAT1 inhibition did not alter the thickness of the actin cortex, a cytoskeleton spreading over the inner surface of the plasma membrane. Even when the actin cortex was disrupted, DESAT1 inhibition still reduced membrane deformability, suggesting that the cellular MUFA content influences the mechanical properties of the phospholipid bilayer itself. Collectively, these results demonstrate that Δ9– desaturase regulates cell membrane deformation by controlling the MUFA content in cellular phospholipid acyl chains.
