Department of Biological Sciences, Ashoka University, Sonepat, Haryana, India.
Commun Biol. 2022 Apr 4;5(1):307. doi: 10.1038/s42003-022-03258-3.
Talin as a critical focal adhesion mechanosensor exhibits force-dependent folding dynamics and concurrent interactions. Being a cytoplasmic protein, talin also might interact with several cytosolic chaperones; however, the roles of chaperones in talin mechanics remain elusive. To address this question, we investigated the force response of a mechanically stable talin domain with a set of well-known unfoldase (DnaJ, DnaK) and foldase (DnaKJE, DsbA) chaperones, using single-molecule magnetic tweezers. Our findings demonstrate that chaperones could affect adhesion proteins' stability by changing their folding mechanics; while unfoldases reduce their unfolding force from ~11 pN to ~6 pN, foldase shifts it upto ~15 pN. Since talin is mechanically synced within 2 pN force ranges, these changes are significant in cellular conditions. Furthermore, we determined that chaperones directly reshape the energy landscape of talin: unfoldases decrease the unfolding barrier height from 26.8 to 21.7 kT, while foldases increase it to 33.5 kT. We reconciled our observations with eukaryotic Hsp70 and Hsp40 and observed their similar function of decreasing the talin unfolding barrier. Quantitative mapping of this chaperone-induced talin folding landscape directly illustrates that chaperones perturb the adhesion protein stability under physiological force, thereby, influencing their force-dependent interactions and adhesion dynamics.
作为一个关键的黏着斑机械感受器，talin 表现出依赖于力的折叠动力学和并发相互作用。作为一种细胞质蛋白，talin 也可能与几种胞质伴侣相互作用；然而，伴侣在 talin 力学中的作用仍然难以捉摸。为了解决这个问题，我们使用单分子磁镊研究了一组已知的解折叠酶（DnaJ、DnaK）和折叠酶（DnaKJE、DsbA）对机械稳定的 talin 结构域的力响应。我们的研究结果表明，伴侣可以通过改变它们的折叠力学来影响黏附蛋白的稳定性；虽然解折叠酶将其解折叠力从11 pN 降低到6 pN，但折叠酶将其提高到~15 pN。由于 talin 在 2 pN 的力范围内是机械同步的，这些变化在细胞条件下是显著的。此外，我们确定伴侣直接重塑了 talin 的能量景观：解折叠酶将解折叠势垒高度从 26.8 降低到 21.7 kT，而折叠酶将其提高到 33.5 kT。我们将我们的观察结果与真核细胞的 Hsp70 和 Hsp40 进行了比较，并观察到它们具有降低 talin 解折叠势垒的类似功能。这种伴侣诱导的 talin 折叠景观的定量映射直接表明，伴侣在生理力下扰乱黏附蛋白的稳定性，从而影响它们依赖于力的相互作用和黏附动力学。
