Figure 1

HSV infection causes a marked decrease of Itch in the presence of UL56. (A) Schematic representation of Itch and UL56. Itch (862 aa) contains a Ca²⁺/lipid binding C2 domain, four WW domains that interact with PY motifs, and a catalytic HECT domain. HSV UL56 (HSV-1, 234 aa; HSV-2, 235 aa) contains three PY motifs and a predicted transmembrane domain (TMD). (B) Infection with wild-type (HSV-1; F, HSV-2; 186) and various mutant HSV (HSV-1; US3-deletion mutant R7041, UL13 deletion mutant R7356, γ₁34.5-deletion mutant R3616, HSV-2; US3-deletion mutant L1BR1, UL56-reverted virus ΔUL56Zrev), but not infection with UL56-deficient HSV (HSV-1; HF10, HSV-2; ΔUL56Z), caused a marked decrease of Itch. Vero cells were mock-infected or infected with wild-type or mutant viruses and harvested at 24 hpi. Nedd4 changed only in cells infected with HSV-2 viruses except ΔUL56Z. WWP2, another Nedd4-family ubiquitin ligase, showed no remarkable change. (C-D) Itch decreases as HSV-2 infection proceeds in Vero, HEp-2 (C), and HaCaT (C, D) cells. Wild-type (186) and ΔUL56Zrev infection caused a marked decrease of Itch. In ΔUL56Z-infected cells, Itch was maintained at almost constant levels for up to 12 hpi. (D) VP5 and VP16 were detected similarly in cells infected with all three viruses. α-tubulin or β-actin were used as loading controls.