Department of Physiology, Microcirculation, Amsterdam Cardiovascular Science, Amsterdam UMC, 1081 HV Amsterdam, The Netherlands.
Department of Medical Oncology, OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, 1081 HV Amsterdam, The Netherlands.
Cells. 2024 Sep 25;13(19):1609. doi: 10.3390/cells13191609.
Cell-cell adhesion in endothelial monolayers is tightly controlled and crucial for vascular integrity. Recently, we reported on the importance of fast protein turnover for maintenance of endothelial barrier function. Specifically, continuous ubiquitination and degradation of the Rho GTPase RhoB is crucial to preserve quiescent endothelial integrity. Here, we sought to identify other barrier regulators, which are characterized by a short half-life, using a proteomics approach. Following short-term inhibition of ubiquitination with E1 ligase inhibitor MLN7243 or Cullin E3 ligase inhibitor MLN4924 in primary human endothelial cells, we identified sixty significantly differentially expressed proteins. Intriguingly, our data showed that AAMP and MTSS1 are novel negative regulators of endothelial barrier function and that their turnover is tightly controlled by ubiquitination. Mechanistically, AAMP regulates the stability and activity of RhoA and RhoB, and colocalizes with F-actin and cortactin at membrane ruffles, possibly regulating F-actin dynamics. Taken together, these findings demonstrate the critical role of protein turnover of specific proteins in the regulation of endothelial barrier function, contributing to our options to target dysregulation of vascular permeability.
细胞间黏附在内皮单层细胞中受到严格控制，对血管完整性至关重要。最近，我们报道了快速蛋白周转对维持内皮屏障功能的重要性。具体而言，Rho GTPase RhoB 的连续泛素化和降解对于保持静止的内皮完整性至关重要。在这里，我们使用蛋白质组学方法来寻找其他半衰期较短的屏障调节剂。在原代人内皮细胞中用 E1 连接酶抑制剂 MLN7243 或 Cullin E3 连接酶抑制剂 MLN4924 短期抑制泛素化后，我们鉴定了六十种差异表达显著的蛋白质。有趣的是，我们的数据表明，AAMP 和 MTSS1 是内皮屏障功能的新型负调节剂，其周转受到泛素化的严格控制。从机制上讲，AAMP 调节 RhoA 和 RhoB 的稳定性和活性，并与膜皱襞处的 F-肌动蛋白和桩蛋白共定位，可能调节 F-肌动蛋白动力学。总之，这些发现表明特定蛋白质的蛋白质周转在调节内皮屏障功能方面起着关键作用，为我们提供了针对血管通透性失调的靶向治疗选择。
