Epstein-Barr virus protein kinase (BGLF4) (BGLF4)

The Epstein-Barr virus protein kinase, encoded by the BGLF4 gene, is a conserved serine/threonine kinase that plays a pivotal role in the lytic phase of the EBV life cycle. As the only protein kinase encoded by EBV, BGLF4 is responsible for phosphorylating numerous viral and cellular proteins, thereby modulating host cell processes such as the cell cycle, nuclear envelope breakdown, and the DNA damage response to favor viral replication (UniProt P03210). It is particularly critical for viral DNA synthesis and the efficient egress of nucleocapsids from the nucleus. In clinical practice, BGLF4 is the primary enzyme that phosphorylates the antiviral prodrug ganciclovir into its active monophosphate form, which is subsequently converted to a triphosphate that inhibits viral DNA polymerase (PubMed: 10823858). Consequently, mutations in the BGLF4 gene are a known mechanism of resistance to ganciclovir therapy in patients with EBV-related diseases. While primarily viewed as a prodrug activator, BGLF4 is also a target for direct kinase inhibitors like maribavir, although its sensitivity is lower than that of the cytomegalovirus homolog UL97 (PubMed: 15105505). Its role in inducing the lytic cycle has also made it a focus for "lytic induction therapy" in EBV-associated malignancies, where forcing viral replication in latent cells can trigger cell death.

Other names

BGLF4EBV-PKEpstein-Barr virus serine/threonine protein kinaseUL97-like kinaseProtein kinase BGLF4

Activation of nucleoside analog prodrugs via phosphorylation to monophosphate forms; direct inhibition of viral kinase activity