Potential origin of the Nup84 complex through ancient gene duplications and losses. A diagram of the Nup84 complex nup arrangement is shown. β-propeller domains are colored in cyan, α-solenoid domains are colored in magenta, and invasion domains (Hsia et al., 2007; Brohawn et al., 2008) are indicated with magenta arrows. The N- and C-terminal ends of each protein are highlighted. The hypothetical duplication axis is shown as a dashed gray line dividing the complex between the Nup145c and Nup84 interaction surfaces. Possible ancestral nups lost after the duplication are shown as faded gray domains.