We examined the PI3K domains between the sequences of PI3K-related proteins and the monkeypox virus E protein F13 using the local MEME software. According to Table , F13 has four PI3K/PI4K motifs and two PIK motifs. PI3K/PI4K and PIK are dispersed over the whole F13 sequence. This shows that the PI3K/PI4K domains of F13 are involved in the first step of the membrane fusion process of the monkeypox virus.