DNA replication licensing factor Cdc6 and Plk4 kinase antagonistically regulate centrosome duplication via Sas-6

Abstract

Centrosome number is tightly controlled during the cell cycle to ensure proper spindle assembly and cell division. However, the underlying mechanism that controls centrosome number remains largely unclear. We show herein that the DNA replication licensing factor Cdc6 is recruited to the proximal side of the centrioles via cyclin A to negatively regulate centrosome duplication by binding and inhibiting the cartwheel protein Sas-6 from forming a stable complex with another centriole duplication core protein, STIL. We further demonstrate that Cdc6 colocalizes with Plk4 at the centrosome, and interacts with Plk4 during S phase. Plk4 disrupts the interaction between Sas-6 and Cdc6, and suppresses the inhibitory role of Cdc6 on Sas-6 by phosphorylating Cdc6. Overexpressing wild-type Cdc6 or Plk4-unphosphorylatable Cdc6 mutant 2A reduces centrosome over-duplication caused by Plk4 overexpression or hydroxyurea treatment. Taken together, our data demonstrate that Cdc6 and Plk4 antagonistically control proper centrosome duplication during the cell cycle.

Cdc6 disruption leads to centrosome abnormalities and chromosome instability in pancreatic cancer cells

“…Moreover, we found that Cdc6 depletion induces a series of abnormal events, including centrosome over-duplication, multipolar spindle formation, and chromosome instability. These results are similar those reported in a previous study that Cdc6 and Plk4 are co-localized at the centrosome and have an important role in efficient centrosome duplication during the cell cycle 13 . Cdc6 depletion promoted apoptotic cell death with increased activation of caspase-3 and caspase-9.…”

“…According to previous research, Cdc6 localizes to the centrosome during the S and G 2 phases of the cell cycle, while a lack of Cdc6 has been shown to cause centrosome over-duplication in U2OS cells 13,14 . Hence, we examined whether Cdc6 depletion induced centrosome over-duplication by transfecting PANC-1 cells with Cdc6 siRNA and staining them with pericentrin (centrosome marker).…”

High PLK4 expression promotes tumor progression and induces epithelial‑mesenchymal transition by regulating the Wnt/β‑catenin signaling pathway in colorectal cancer Corrigendum in /10.3892/ijo.2021.5213

“…Polo-like kinase 4 (PLK4), which is a member of the polo family of serine/threonine protein kinases, localizes to centrioles, which are complex microtubule-based structures present in centrosomes ( 6 , 7 ). PLK4 functions primarily as a regulator that mediates centriole duplication during the cell cycle ( 8 ).…”

Use of the Polo-like kinase 4 (PLK4) inhibitor centrinone to investigate intracellular signalling networks using SILAC-based phosphoproteomics

“…PLK4 binds directly to the N-terminal region of CDC6 in S-phase, disrupting the CDC6 Sas-6 interaction following CDC6 phosphorylation. Based on prediction and mutational analysis, PLK4 was previously shown to phosphorylate CDC6 in vitro on Ser30 and Thr527 [82]. Based on our data, we suggest that Ser74, which is conserved in ∼70% of aligned eukaryotic orthologues, is a potential additional phosphosite on CDC6 that lies in a SerPro consensus downstream of centrinone in cells [82].…”