The SAH domain binds MTs to sustain the SAC. (A) LAP-tagged hINCENP constructs. (B) Immunofluorescence of hINCENP ΔSAH∇MAP4 expressed over endogenous INCENP in asynchronous HeLa cells. Bar, 2 µm. (C) DoM for cells in taxol. Red values are the percentage cell death for each construct. (D and E) Immunofluorescence quantification of BubR1 in taxol-treated cells (D) and SAC proteins and Aurora B–dependent phosphorylation in nocodazole-treated cells (E) expressing the indicated constructs. In D, the data represent integrated intensity at the kinetochore from n ≥ 27 cells. In E, the data represent integrated intensity at the kinetochore from n ≥ 54 cells aggregated from three independent experiments for Bub1 and BubR1, and n ≥ 1,720 individual kinetochore measurements for Dsn1 S100ph and Knl1 S24ph using a marker epitope. Representative images approximate the median. Two-tailed Mann–Whitney t test; ns, not significant; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001. Bar, 2 µm. (F) Immunofluorescence quantification of Hec1 S44ph at individual kinetochores standardized to total Hec1 at that kinetochore for cells treated with nocodazole. The data are visualized as a kernel density estimate, n values indicated under the sample name. ZM, the Aurora B inhibitor ZM447439. The maximum height of the density for ZM-treated cells was scaled independently.