Plays an essential role in cytoplasmic secondary envelopment during viral egress. Interacts with the capsid via the large tegument protein/LTP and participates in its transport to the host trans-Golgi network (TGN) where secondary envelopment occurs. Modulates tegumentation and capsid accumulation at the viral assembly complex. Interacts (via C-terminus) with the large tegument protein/LTP (via N-terminus). Belongs to the herpesviridae inner tegument protein family.