LRRC8 family proteins within lysosomes regulate cellular osmoregulation and enhance cell survival to multiple physiological stresses
Ping Li, Meiqin Hu, Ce Wang, Xinghua Feng, Zhuangzhuang Zhao, Ying Yang, Nirakar Sahoo, Mingxue Gu, Yexin Yang, Shiyu Xiao, Rajan Sah, Timothy L. Cover, Janet Chou, Raif S. Geha, Fernando Benavides, Richard I. Hume, Haoxing Xu
Abstract
motif at the C terminus of LRRC8A was mutated to alanines, normal plasma membrane VRAC currents were still observed, but Lyso-VRAC currents were absent. We used this targeting mutant, as well as pharmacological tools, to demonstrate that Lyso-VRAC currents are necessary for the formation of large lysosome-derived vacuoles, which store and then expel excess water to maintain cytosolic water homeostasis. Thus, Lyso-VRACs allow lysosomes of mammalian cells to act as the cell`s "bladder." When Lyso-VRAC current was selectively eliminated, the extent of necrotic cell death to sustained stress was greatly increased, not only in response to hypoosmotic stress, but also to hypoxic and hypothermic stresses. Thus Lyso-VRACs play an essential role in enabling cells to mount successful homeostatic responses to multiple stressors.