Sak/Plk4 and mitotic fidelity

SAPK pathways and p53 cooperatively regulate PLK4 activity and centrosome integrity under stress

“…In particular, PLK4 phosphorylation at T170 in the kinase activation loop is essential for the catalytic activity of PLK4 (ref. 20). The upstream kinases that are responsible for T170 phosphorylation, however, have not been identified.…”

“…To test if these kinases phosphorylate the essential activating phosphorylation site (T170) of PLK4 (ref. 20), we generated an antibody against phosphorylated T170 (Supplementary Fig. S2e).…”

“…Therefore, PLK4 activity must be adequately controlled to maintain centrosome integrity and to prevent carcinogenesis. During normal cell-cycle progression, the levels of PLK4 transcripts are low in G1, gradually increase through S and G2, and reach a maximum in mitosis 20 . Regulatory mechanisms of PLK4 activity, however, remain obscure.…”

Human Plk4 phosphorylates Cdc25C

“…For example, all the Plk family members have been shown to interact with p53. 7,10 Furthermore, Plk1 and Plk3 have both been shown to phosphorylate Cdc25C phosphatase thus resulting in its localization to the nucleus. 11,12 Nuclear localization and activation of this protein are necessary in order for mitosis to occur.…”

Proteomic Analysis of Wnt-Dependent Dishevelled-Based Supermolecular Complexes

“…PTPRR associates with MAPKs and inactivates kinases by dephosphorylating tyrosine residue (Hendriks et al, 2009). MAPKs promote Wnt/β-catenin signaling pathway via LRP6 phosphorylation suggesting convergence between Wnt/β-catenin signaling pathway and the mitogenic pathway (Swallow et al, 2005). PLK4 is required for the reproduction of centrosomes during cell cycle (Habedanck et al, 2005 …”