VRK2

VRK2 (vaccinia-related kinase 2) is a serine/threonine kinase of the VRK family that regulates multiple signal transduction pathways involved in cellular stress responses, apoptosis, and growth control^[1][2]. Distinct subcellular localization underlies important functional specialization, with the membrane-anchored isoform VRK2A predominantly associated with the endoplasmic reticulum and mitochondrial membranes, whereas VRK2B displays a broader cytosolic and nuclear distribution, leading to different effects on downstream signaling and protein regulation^[3][4]. Mechanistically, VRK2 modulates MAPK-associated signaling through interactions with scaffold proteins, including JIP1 and KSR1, thereby influencing JNK and ERK pathway activity and shaping cellular responses to cytokines, hypoxia, and other stress stimuli^[5][6][7]. Through these signaling functions, VRK2 contributes to the regulation of apoptosis, where VRK2A interacts with Bcl-xL and suppresses BAX-dependent mitochondrial apoptotic activation, promoting cell survival under stress conditions^[8][9]. In disease contexts, altered VRK2 activity has been implicated in cancer progression, tumor cell invasion, and neurological disorders, including schizophrenia and epilepsy, supporting its relevance as a regulator of both oncogenic and neuronal signaling networks^[10][11][12]. Compared with its paralog VRK1, VRK2 is distinguished by its membrane-associated localization, signaling scaffold interactions, and isoform-dependent biological activities, which provide unique opportunities for mechanistic studies of compartmentalized kinase signaling^[3][6][13]. Currently, selective pharmacological modulators of VRK2 remain limited, and experimental investigations primarily rely on genetic perturbation and pathway-based approaches to define VRK2-dependent biological functions^[10].