Neutral lipids (NLs) are apolar oil molecules synthesized in the endoplasmic reticulum (ER) bilayer upon diverse biological stimuli. NLs synthesized are released in the hydrophobic core of the bilayer. At a critical concentration, NLs condense by phase separation and nucleate a lipid droplet (LD). After an LD forms, a fraction of NLs can be present in the bilayer but at a concentration below that of the nucleation. Here, we study whether and how the accumulation of NLs alters a lipid bilayer's mechanical properties. In synthetic systems, we found that NLs proffer unusual bilayer stretching capacities, especially in the presence of negatively curved phospholipids. This impact becomes spectacular when a lipid droplet is contiguous with the bilayer and supplies it with NLs. The tested NLs markedly decrease the bilayer area expansion modulus, significantly increase lysis tension but had opposite effects on membrane bending rigidity. Our data unveil how NL molecules modify overall membrane mechanics, the alteration of which may be linked to pathologies or anticancer treatments targeting NLs.

中文翻译：

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脂肪夹杂物强烈改变膜力学。

中性脂质 (NLs) 是在内质网 (ER) 双层中在多种生物刺激下合成的非极性油分子。合成的 NL 在双层的疏水核心中释放。在临界浓度下，NLs 通过相分离凝聚并形成脂滴 (LD)。在 LD 形成后，一部分 NL 可以存在于双层中，但浓度低于成核浓度。在这里，我们研究了 NLs 的积累是否以及如何改变脂质双层的机械性能。在合成系统中，我们发现 NL 提供了不寻常的双层拉伸能力，特别是在存在负弯曲磷脂的情况下。当脂滴与双层相邻并为其提供 NL 时，这种影响会变得非常壮观。测试的 NL 显着降低了双层面积膨胀模量，显着增加裂解张力，但对膜弯曲刚度有相反的影响。我们的数据揭示了 NL 分子如何改变整体膜力学，其改变可能与针对 NL 的病理学或抗癌治疗有关。