Fig. 4

CHEK1 promotes CIN through CEP170 activation in MM. A–B Centrosomal Protein 170 (CEP170) was selected among candidate genes of the CIN-related gene list and genes associated with poor outcome in the TT2 MM patient cohort. C Increased CEP170 expression was associated with decreased OS in the TT2 patient cohort. D A Co-IP assay revealed that CHEK1 directly interacted with CEP170 in CHEK1-OE ARP1 and H929 cells. E–F CEP170 OE significantly increased chromosomal plate width and decreased mitotic bipolar spindle length in ARP1 and H929 cells. G A Co-IP assay confirmed that CHEK1 physically interacted with and phosphorylated CEP170 in CHEK1-OE cells compared with WT cells, as detected by total anti-phospho-serine antibody. H Mass spectrometry (MS) was used to determine the CHEK1 phosphorylation site of CEP170, Ser1260. I A Myc-tagged CEP170 Ser1260Ala mutant, containing a defective CHEK1 phosphorylation site, exhibited dramatically decreased interaction with flag-tagged CHEK1, as demonstrated by Co-IP followed by western blotting. J–K OE of mutated CEP170 Ser1260Ala decreased chromosomal plate width and increased mitotic bipolar spindle length in (J) ARP1 and (K) H929 cells