Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA.
Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA.
Nucleus. 2023 Dec;14(1):2180206. doi: 10.1080/19491034.2023.2180206.
Lamins A/C are nuclear intermediate filament proteins that are involved in diverse cellular mechanical and biochemical functions. Here, we report that recognition of Lamins A/C by a commonly used antibody (JOL-2) that binds the Lamin A/C Ig-fold and other antibodies targeting similar epitopes is highly dependent on cell density, even though Lamin A/Clevels do not change. We propose that the effect is caused by partial unfolding or masking of the C'E and/or EF loops of the Ig-fold in response to cell spreading. Surprisingly, JOL-2 antibody labeling was insensitive to disruption of cytoskeletal filaments or the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. Furthermore, neither nuclear stiffness nor nucleo-cytoskeletal force transmission changed with cell density. These findings are important for the interpretation of immunofluorescence data for Lamin A/C and also raise the intriguing prospect that the conformational changes may play a role in Lamin A/C mediated cellular function.
核纤层蛋白 A/C 是一种核中间丝蛋白，参与多种细胞力学和生化功能。在这里，我们报告说，一种常用的抗体（JOL-2）识别核纤层蛋白 A/C，该抗体结合核纤层 A/C Ig 折叠和其他针对相似表位的抗体，高度依赖于细胞密度，尽管核纤层蛋白 A/C 水平没有变化。我们提出，这种效应是由于 Ig 折叠的 C'E 和/或 EF 环部分展开或被掩盖，以响应细胞扩展。令人惊讶的是，JOL-2 抗体标记对细胞骨架丝或核骨架和细胞骨架连接体（LINC）复合物的破坏不敏感。此外，核硬度和核-细胞骨架力传递都不会随细胞密度而变化。这些发现对核纤层蛋白 A/C 的免疫荧光数据的解释很重要，并且提出了一个有趣的观点，即构象变化可能在核纤层蛋白 A/C 介导的细胞功能中发挥作用。
