The UL9 protein is phosphorylated in HSV-1 infected cells by celluar kinase(s).
In neurons, the phosphorylated UL9 protein can be recognized by NFB42, a
neuron-specific F-box protein. NFB42 is linked to the SCF complex by interaction
between the F box with NFB42 and Skp1, which results in the formation of
SCFNFB42 Skp1 also binds to cullin-1: Cdc34, an E2 ubiquitin-conjugating enzyme,
binds to the SCFNFB42 and ubiquitnates the UL9 protein bound to NFB42. Rbx1
functions in E2 recruitment. Cullin-1 functions as a bridge molecule in the SCF
complex. The polyubiquitinated UL9 proteins are degraded by the 265 proteasome,
leading to the inhibition of initiation of HSV-1 DNA replication and, ultimately,
to neuronal HSV-1 latency.
NFB42 mediates the
nuclear export of the
herpes virus DNA
replication initiator
protein after viral
infection.