Molecular Dynamics Simulation Analysis of JAK1 Initial Activation: Phosphorylation-Induced Conformational Dynamics...

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Janus kinase (JAK) is crucial for cytokine signaling.
• JAK hyperactivation drives various diseases.
• The precise activation mechanism of JAK1 remains elusive.

Purpose of the Study:

• To investigate the role of tyrosine residues Y1034 and Y1035 in JAK1 activation.
• To elucidate the molecular mechanisms of JAK1 conformational changes.
• To provide insights for therapeutic targeting of JAK1.

Main Methods:

• Utilized molecular dynamics (MD) simulations.
• Analyzed conformational transitions of the JAK1 tyrosine kinase (TK) domain.
• Investigated the impact of phosphorylation at Y1034 and Y1035.

Main Results:

• Bisphosphorylation at Y1034 and Y1035 promotes the transition to JAK1's open conformation.
• pY1035 has a more significant role than pY1034 in promoting opening.
• Phosphorylation increases negative surface charge, aiding TK-FERM domain dissociation.
• Stable hydrogen bonds in a loop region partially hinder full activation.

Conclusions:

• Phosphorylation of Y1034 and Y1035 is critical for initial JAK1 activation.
• pY1035 plays a dominant role in the conformational shift to the open state.
• Understanding these mechanisms can inform strategies for treating JAK1-related diseases.