Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
Department of Mechanical Engineering, Kennesaw State University. Marietta, GA 30060, USA.
J Cell Sci. 2020 Oct 21;133(20):jcs240341. doi: 10.1242/jcs.240341.
All mammalian cells live in the aqueous medium, yet for many cell biologists, water is a passive arena in which proteins are the leading players that carry out essential biological functions. Recent studies, as well as decades of previous work, have accumulated evidence to show that this is not the complete picture. Active fluxes of water and solutes of water can play essential roles during cell shape changes, cell motility and tissue function, and can generate significant mechanical forces. Moreover, the extracellular resistance to water flow, known as the hydraulic resistance, and external hydraulic pressures are important mechanical modulators of cell polarization and motility. For the cell to maintain a consistent chemical environment in the cytoplasm, there must exist an intricate molecular system that actively controls the cell water content as well as the cytoplasmic ionic content. This system is difficult to study and poorly understood, but ramifications of which may impact all aspects of cell biology from growth to metabolism to development. In this Review, we describe how mammalian cells maintain the cytoplasmic water content and how water flows across the cell surface to drive cell movement. The roles of mechanical forces and hydraulic pressure during water movement are explored.
所有哺乳动物细胞都生活在水相环境中，但对于许多细胞生物学家来说，水是一个被动的舞台，其中蛋白质是发挥基本生物功能的主要参与者。最近的研究以及几十年的前期工作积累的证据表明，事实并非如此。水的主动流动和溶质可以在细胞形态变化、细胞运动和组织功能中发挥重要作用，并能产生显著的机械力。此外，水流动的细胞外阻力，即液压阻力，以及外部液压压力是细胞极化和运动的重要机械调节剂。为了使细胞在细胞质中保持一致的化学环境，必须存在一个复杂的分子系统，该系统主动控制细胞的含水量以及细胞质的离子含量。这个系统很难研究，也不太了解，但它的影响可能会涉及细胞生物学的各个方面，从生长到代谢再到发育。在这篇综述中，我们描述了哺乳动物细胞如何维持细胞质的含水量，以及水如何穿过细胞膜表面驱动细胞运动。还探讨了在水流动过程中机械力和液压压力的作用。
