Phosphorylation of MEK4 by MEKK1 (Xenopus tropicalis)
phosphorylation of mek4 by mekk1 (xenopus tropicalis)
Phosphorylation of MEK4 by MEKK1 (Xenopus tropicalis)
phosphorylation of mek4 by mekk1 (xenopus tropicalis)