WNK2 and neurodegenerative disease: Recently, ROS has been appreciated as a crucial player in multiple diseases (e.g. male infertility, cancers and neurodegenerative diseases) due to its regulatory effects on cell signaling proteins (e.g. NF-κB, mitogen-activated protein kinases (MAPKs) and PI3K-Akt), protein kinases and ubiquitination/proteasome system [30–33].