K_v1.3 induced hyperpolarisation and Ca_v3.2-mediated calcium entry are required for efficient Kaposi’s sarcoma-associated herpesvirus lytic replication

Understanding the host factors critical for Kaposi’s sarcoma-associated herpesvirus (KSHV) lytic replication can identify new targets for therapeutic intervention. Using pharmacological and genetic silencing approaches, we reveal for the first time that KSHV requires a B cell expressed voltage-gated K⁺ channel, K_v1.3, to enhance lytic replication. We show that the KSHV replication and transcription activator (RTA) protein upregulates K_v1.3 expression, leading to enhanced K⁺ channel activity and hyperpolarisation of the B cell membrane. Enhanced K_v1.3 activity then promotes intracellular Ca²⁺ influx through Ca_v3.2, a T-type Ca²⁺ channel, leading to the Ca²⁺ driven nuclear localisation of NFAT and the subsequent NFAT1-responsive gene expression. Importantly, KSHV lytic replication and infectious virion production could be inhibited by both K_v1.3 and Ca_v3.2 blockers or through K_v1.3 silencing. These findings provide new mechanistic insight into the essential role of host ion channels during KSHV infection and highlight K_v1.3 and Ca_v3.2 as new druggable host factors that are key to the successful completion of KSHV lytic replication.