Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065.
Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, NY 10065.
Proc Natl Acad Sci U S A. 2022 Jan 4;119(1). doi: 10.1073/pnas.2112390119.
When nuclear membranes are stretched, the peripheral membrane enzyme cytosolic phospholipase A2 (cPLA) binds via its calcium-dependent C2 domain (cPLA-C2) and initiates bioactive lipid signaling and tissue inflammation. More than 150 C2-like domains are encoded in vertebrate genomes. How many of them are mechanosensors and quantitative relationships between tension and membrane recruitment remain unexplored, leaving a knowledge gap in the mechanotransduction field. In this study, we imaged the mechanosensitive adsorption of cPLA and its C2 domain to nuclear membranes and artificial lipid bilayers, comparing it to related C2-like motifs. Stretch increased the Ca sensitivity of all tested domains, promoting half-maximal binding of cPLA at cytoplasmic resting-Ca concentrations. cPLA-C2 bound up to 50 times tighter to stretched than to unstretched membranes. Our data suggest that a synergy of mechanosensitive Ca interactions and deep, hydrophobic membrane insertion enables cPLA-C2 to detect stretched membranes with antibody-like affinity, providing a quantitative basis for understanding mechanotransduction by C2-like domains.
当核膜被拉伸时，外周膜酶细胞质磷脂酶 A2（cPLA）通过其依赖于钙的 C2 结构域（cPLA-C2）结合，并启动生物活性脂质信号和组织炎症。脊椎动物基因组中编码了超过 150 个 C2 样结构域。其中有多少是机械感受器，以及张力和膜募集之间的定量关系仍未被探索，这使得机械转导领域存在知识空白。在这项研究中，我们对 cPLA 及其 C2 结构域与核膜和人工脂质双层的机械敏感吸附进行了成像，并将其与相关的 C2 样基序进行了比较。拉伸增加了所有测试结构域的钙敏感性，促进了 cPLA 在细胞质静止 Ca 浓度下的半最大结合。cPLA-C2 与拉伸膜的结合比未拉伸膜紧密 50 倍。我们的数据表明，机械敏感的 Ca 相互作用和深的疏水性膜插入的协同作用使 cPLA-C2 能够以类似于抗体的亲和力检测拉伸膜，为理解 C2 样结构域的机械转导提供了定量基础。
