Dissecting the Multiple Functions of the Polo-Like Kinase 1 in the C. elegans Zygote.

Plk1 (polo-like kinase 1) is an evolutionarily conserved serine/threonine kinase instrumental for mitotic entry and progression. Beyond these canonical functions, Plk1 also regulates cell polarization and cell fate during asymmetric cell divisions in C. elegans and D. melanogaster. Plk1 contains a specialized phosphoserine-threonine binding domain, the polo-box domain (PBD), which localizes and concentrates the kinase at its various sites of action within the cell in space and time. Here we present protocols to express and purify the C. elegans Plk1 kinase along with biochemical and phosphoproteomic approaches to interrogate the PBD interactome and to dissect Plk1 substrate interactions. These protocols are most suitable for the identification of Plk1 targets in C. elegans embryos but can be easily adapted to identify and study Plk1 substrates from any source."