Inference of Multisite Phosphorylation Rate Constants and Their Modulation by Pathogenic Mutations

Area of Science:

• Cellular signaling
• Biochemistry
• Enzyme kinetics

Background:

• Multisite protein phosphorylation is crucial for cellular regulation.
• The kinetics and order of phosphorylation steps are vital for function but poorly understood.
• Dual phosphorylation, specifically of ERK, serves as a model for these complex processes.

Purpose of the Study:

• To investigate the kinetic mechanisms of dual phosphorylation of ERK by MEK.
• To analyze the impact of pathogenic mutations on enzyme processivity and phosphorylation efficiency.
• To establish a framework connecting mutations to kinetic parameters for multisite phosphorylation.

Main Methods:

• Utilized Bayesian parameter inference.
• Employed a structurally identifiable kinetic model.
• Focused on the dual phosphorylation of ERK by MEK.

Main Results:

• Dissected the kinetic parameters governing dual phosphorylation of ERK.
• Quantified how enzyme processivity and phosphorylation step efficiencies are altered by mutations.
• Identified specific kinetic changes associated with pathogenic mutations in MEK.

Conclusions:

• The study provides a systematic framework to link enzyme kinetics to multisite phosphorylation mechanisms.
• Understanding these kinetics is essential for bridging in vitro enzyme studies with in vivo biological effects.
• This approach offers insights into disease mechanisms driven by mutations in kinases like MEK.