Integrative structural modeling of a multidomain polo-like kinase

Area of Science:

• Molecular Biology
• Structural Biology
• Cell Biology

Background:

• Polo-like kinase 1 (PLK1) is essential for regulating mitosis.
• PLK1 comprises a kinase domain (KD) and a polo-box domain (PBD).
• The interaction between KD and PBD in full-length PLK1 is not well understood.

Purpose of the Study:

• To elucidate the structural architecture of full-length PLK1.
• To investigate the interaction between the KD and PBD in solution.
• To understand how KD-PBD interactions regulate PLK1 kinase activity.

Main Methods:

• Integrated structural data from small-angle X-ray scattering (SAXS) and hydroxyl radical protein footprinting.
• Employed computational sampling techniques.
• Utilized site-directed mutagenesis to disrupt the KD-PBD interface.

Main Results:

• A model for PLK1 multidomain assembly between KD and PBD was determined.
• The KD interacts with the PBD via its C-lobe in an auto-inhibited state.
• Disruption of the KD-PBD interface increased PLK1 kinase activity.

Conclusions:

• Full-length human PLK1 adopts dynamic structures with varied domain-domain interfaces in solution.
• KD-PBD interactions play a critical role in regulating PLK1 kinase function.
• This study provides insights into the structural basis of PLK1 regulation.