Large tegument protein that plays multiple roles in the viral cycle. During viral entry, remains associated with the capsid while most of the tegument is detached and participates in the capsid transport toward the host nucleus. Plays a role in the routing of the capsid at the nuclear pore complex and subsequent uncoating. Within the host nucleus, acts as a deneddylase and promotes the degradation of nuclear CRLs (cullin-RING ubiquitin ligases) and thereby stabilizes nuclear CRL substrates, while cytoplasmic CRLs remain unaffected. These modifications prevent host cell cycle S-phase progression and create a favorable environment allowing efficient viral genome replication. Participates later in the secondary envelopment of capsids. Indeed, plays a linker role for the association of the outer viral tegument to the capsids together with the inner tegument protein