Phosphorylation by Cdk1 induces Plk1-mediated vimentin phosphorylation during mitosis

Abstract

Several kinases phosphorylate vimentin, the most common intermediate filament protein, in mitosis. Aurora-B and Rho-kinase regulate vimentin filament separation through the cleavage furrow-specific vimentin phosphorylation. Cdk1 also phosphorylates vimentin from prometaphase to metaphase, but its significance has remained unknown. Here we demonstrated a direct interaction between Plk1 and vimentin-Ser55 phosphorylated by Cdk1, an event that led to Plk1 activation and further vimentin phosphorylation. Plk1 phosphorylated vimentin at ∼1 mol phosphate/mol substrate, which partly inhibited its filament forming ability, in vitro. Plk1 induced the phosphorylation of vimentin-Ser82, which was elevated from metaphase and maintained until the end of mitosis. This elevation followed the Cdk1-induced vimentin-Ser55 phosphorylation, and was impaired by Plk1 depletion. Mutational analyses revealed that Plk1-induced vimentin-Ser82 phosphorylation plays an important role in vimentin filaments segregation, coordinately with Rho-kinase and Aurora-B. Taken together, these results indicated a novel mechanism that Cdk1 regulated mitotic vimentin phosphorylation via not only a direct enzyme reaction but also Plk1 recruitment to vimentin.

Dronc caspase exerts a non-apoptotic function to restrain phospho-Numb-induced ectopic neuroblast formation in Drosophila

“…In this study, we present evidence that phosphorylation of Numb at the putative Polo sites primarily affect Numb activity in negatively regulating Notch signaling through promoting the endocytosis of Spdo. Although not all the identified Polo phosphorylation sites in Numb perfectly match the optimal consensus sequence initially defined for Polo (Nakajima et al, 2003), the Polo consensus sequence being defined is evolving (Barr et al, 2004), and specific characterized phosphorylation sites in other Polo substrates actually do not conform to the above consensus sequences (Toyoshima-Morimoto et al, 2001;Casenghi et al, 2003;Jackman et al, 2003;Yamaguchi et al, 2005;Mbefo et al, 2010;Yim and Erikson, 2010;Jang et al, 2011;Rizkallah et al, 2011). A common feature appears to be negatively charged residues surrounding the S/T residues; all five sites identified in Numb have this feature.…”

“…Two conserved residues, S183 and S188, are located within the phospho-tyrosine binding (PTB) domain that is essential for Numb activity (Frise et al, 1996). The sequences flanking these residues resemble phosphorylation sites for Polo kinase, with at least one negatively charged D/E residues at the -3 to +3 positions (Kelm et al, 2002;Nakajima et al, 2003;Barr et al, 2004;Yamaguchi et al, 2005;Mbefo et al, 2010) (see Fig. S1 in the supplementary material).…”

Cdk1/Cyclin B-Mediated Phosphorylation Stabilizes SREBP1 During Mitosis

“…A priming role of the Cdk1 complex in the mitotic phosphorylation of proteins have been described for other Cdk1 substrates, including N-Myc, Nir2 and vimentin. [29][30][31] In many cases, Cdk1-mediated phosphorylation generates a binding site for other mitotic kinases. [29][30][31][32][33][34] It will, therefore, be interesting to Cdk1 Regulates SREBP1 determine whether phospho-S439 in SREBP1 will function as a docking site for other proteins, including mitotic kinases.…”

Phosphorylation by polo-like kinase 1 induces the tumor-suppressing activity of FADD

“…Collectively, our data indicate that Ser-194 residue of FADD is phosphorylated by Plk1. However, Plk1 has been shown to phosphorylate other proteins that do not contain this consensus motif, such as GRASP65 and vimentin (Preisinger et al, 2005;Yamaguchi et al, 2005). P-FADD mediates the degradation of Plk1 in an Ub-independent and proteasome-dependent manner We transfected FADD into HeLa cells in order to understand the implication of the interaction between FADD and Plk1.…”