Coordinates the incorporation of A36 into wrapped enveloped virion (EV) membranes and, subsequently, the production of actin tails. Therefore plays an essential role in efficient cell-to-cell spread of viral particles. Homodimer, disulfide-linked. Interacts with protein B5. Interacts (via C-terminus) with protein A36. Component of the enveloped virion (EV) membrane. Belongs to the chordopoxvirinae A33 protein family.