Schematic diagram of Ndc80c. Residue numbers for key junction points in the S. cerevisiae sequences shown. Solid ovals represent the CH domains of Ndc80 (red) and Nuf2 (orange) at one end and the RWD domains of Spc24 (blue) and Spc25 (green) at the other. The positions of the Ndc80c hinge, loop and the four-way junction are boxed and labelled, respectively. The locations of the three interactions, defined by cross-linking mass spectrometry [1], between Ndc80c and C-terminal extensions of DASH/Dam1c subunits are indicated. The interaction of Stu2 with the tetramerization domain is also indicated. Interaction A involves Dam1, interaction B, Ask1 and interactions C, Spc19 : Spc34.