Heat shock proteins (HSP) are critical elements for the preservation of cellular homeostasis by participating in an array of biological processes. In addition, HSP play an important role in cellular protection from various environmental stresses. HSP are part of a large family of different molecular mass polypeptides, displaying various expression patterns, subcellular localizations, and diversity functions. An unexpected observation was the detection of HSP on the cell surface. Subsequent studies have demonstrated that HSP have the ability to interact and penetrate lipid bilayers by a process initiated by the recognition of phospholipid heads, followed by conformational changes, membrane insertion, and oligomerization. In the present study, we described the interaction of HSPA8 (HSC70), the constitutive cytosolic member of the HSP70 family, with lipid membranes. HSPA8 showed high selectivity for negatively charged phospholipids, such as phosphatidylserine and cardiolipin, and low affinity for phosphatidylcholine. Membrane insertion was mediated by a spontaneous process driven by increases in entropy and diminished by the presence of ADP or ATP. Finally, HSPA8 was capable of driving into the lipid bilayer HSP90 that does not display any lipid biding capacity by itself. This observation suggests that HSPA8 may act as a membrane chaperone.

热休克蛋白（HSP）是通过参与一系列生物过程来维持细胞稳态的关键元件。此外，HSP 在保护细胞免受各种环境压力方面发挥着重要作用。 HSP 是不同分子量多肽大家族的一部分，表现出不同的表达模式、亚细胞定位和多样性功能。一个意想不到的观察结果是在细胞表面检测到 HSP。随后的研究表明，HSP 具有相互作用和穿透脂质双层的能力，该过程由磷脂头识别启动，随后发生构象变化、膜插入和寡聚化。在本研究中，我们描述了 HSPA8 (HSC70)（HSP70 家族的组成型胞质成员）与脂质膜的相互作用。 HSPA8 对带负电的磷脂（例如磷脂酰丝氨酸和心磷脂）表现出高选择性，而对磷脂酰胆碱则表现出低亲和力。膜插入是由熵增加驱动的自发过程介导的，并因 ADP 或 ATP 的存在而减少。最后，HSPA8 能够驱动脂质双层 HSP90，而 HSP90 本身并不表现出任何脂质结合能力。这一观察结果表明 HSPA8 可能充当膜伴侣。