Department of Biology and Genetics Institute, University of Florida, Gainesville, FL 32611, USA.
Am J Physiol Regul Integr Comp Physiol. 2013 Aug 1;305(3):R175-86. doi: 10.1152/ajpregu.00109.2013. Epub 2013 Jun 5.
Intracellular salt and water homeostasis is essential for all cellular life. Extracellular salt and water homeostasis is also important for multicellular organisms. Many fundamental mechanisms of compensation for osmotic perturbations are well defined and conserved. Alternatively, molecular mechanisms of detecting salt and water imbalances and regulating compensatory responses are generally poorly defined for animals. Throughout the last century, researchers studying vertebrates and vertebrate cells made critical contributions to our understanding of osmoregulation, especially mechanisms of salt and water transport and organic osmolyte accumulation. Researchers have more recently started using invertebrate model organisms with defined genomes and well-established methods of genetic manipulation to begin defining the genes and integrated regulatory networks that respond to osmotic stress. The nematode Caenorhabditis elegans is well suited to these studies. Here, I introduce osmoregulatory mechanisms in this model, discuss experimental advantages and limitations, and review important findings. Key discoveries include defining genetic mechanisms of osmolarity sensing in neurons, identifying protein damage as a sensor and principle determinant of hypertonic stress resistance, and identification of a putative sensor for hypertonic stress associated with the extracellular matrix. Many of these processes and pathways are conserved and, therefore, provide new insights into salt and water homeostasis in other animals, including mammals.
细胞内盐和水的动态平衡对所有细胞生命都是至关重要的。细胞外的盐和水动态平衡对多细胞生物也很重要。许多应对渗透胁迫的补偿的基本机制已经得到了很好的定义和保存。相反，对于动物来说，检测盐和水失衡以及调节补偿反应的分子机制通常定义不明确。在过去的一个世纪里，研究脊椎动物和脊椎动物细胞的研究人员对我们对渗透压调节的理解做出了重要贡献，特别是盐和水转运和有机渗透物积累的机制。研究人员最近开始使用具有明确基因组和成熟遗传操作方法的无脊椎动物模式生物，开始定义对渗透胁迫做出反应的基因和综合调控网络。秀丽隐杆线虫非常适合这些研究。在这里，我介绍了这个模型中的渗透压调节机制，讨论了实验的优缺点，并回顾了重要的发现。关键的发现包括定义了神经元中渗透压感应的遗传机制，确定了蛋白质损伤作为感受和决定高渗胁迫抗性的主要因素，并确定了一种与细胞外基质相关的高渗应激的潜在传感器。这些过程和途径中有许多是保守的，因此为包括哺乳动物在内的其他动物的盐和水动态平衡提供了新的见解。
