Fig. 4.

Ser894 of INCENP is phosphorylated in response to mitotic spindle damage. (A) Western blots showing phosphorylation of S894 on endogenous INCENP throughout the cell cycle. The pS894-specific bands were abolished by peptide competition with phosphorylated peptide antigen (second panel from top). Asterisks indicate non-specific bands. Aurora-A is a mitotic marker, and α-tubulin is a loading control. (B) Intensity of the pS894-specific band was reduced by siRNA-mediated knockdown of INCENP in mitotic HeLa-S3 cells (lanes 2 and 4, arrowheads). INCENP-depleted cell extracts (siINCENP) were subjected to western blotting with the indicated antibodies. siControl is a negative control. Single and double asterisks indicate non-specific bands and putative degradation products of pS894-INCENP, respectively. See Fig. S2 for uncropped western blot images in Fig. 4A, B. Black boxes indicate the cropped regions. Molecular sizes (kDa) are based on prestained protein markers.