Crystal structure of the N-terminal domain of the human protooncogene Nup214/CAN

The mammalian nuclear pore complex (NPC) is an ≈120-MDa proteinaceous assembly consisting of ≈30 proteins and is the sole gate in the nuclear envelope. The human protooncogene Nup214 was first identified as a target for chromosomal translocation involved in leukemogenesis. Nup214 is located on the cytoplasmic face of the NPC and is implicated in anchoring the cytoplasmic filaments of the NPC and recruiting the RNA helicase Ddx19. Here, we present the crystal structure of the human Nup214 N-terminal domain at 1.65-Å resolution. The structure reveals a seven-bladed β-propeller followed by a 30-residue C-terminal extended peptide segment, which folds back onto the β-propeller and binds to its bottom face. The β-propeller repeats lack any recognizable sequence motif and are distinguished by extensive insertions between the canonical β-strands. We propose a mechanism by which the C-terminal peptide extension is involved in NPC assembly.