Mapping Phosphorylation-Specific Pin1-CRMP2 Interactions Using an Integrated Mass Spectrometry Approach.

Area of Science:

• Neuroscience
• Biochemistry
• Molecular Biology

Background:

• Abnormal protein phosphorylation drives Alzheimer's Disease (AD) pathogenesis, forming neurofibrillary tangles.
• Pin1, a cis-trans prolyl isomerase, is implicated in AD progression and regulates phosphoprotein function.

Purpose of the Study:

• To investigate the molecular interaction between Pin1 and Collapsin Response Mediator Protein-2 (CRMP2).
• To elucidate the role of Pin1 in modulating CRMP2 phosphorylation in the context of Alzheimer's Disease.

Main Methods:

• Native mass spectrometry to identify Pin1-CRMP2 binding.
• Hydrogen-deuterium exchange mass spectrometry to map the binding interface.
• Analysis of CRMP2 phosphorylation sites (Thr509, Thr514) and their impact on binding affinity.

Main Results:

• A novel interaction interface between Pin1 and the C-terminus of CRMP2 was identified.
• Pin1 binding to CRMP2 is phosphorylation-dependent, with specific residues enhancing affinity.
• The WW domain of Pin1 was localized as the binding site for CRMP2.

Conclusions:

• Pin1 binds to hyperphosphorylated CRMP2, a component of neurofibrillary tangles.
• These findings suggest a regulatory mechanism for Pin1 in modulating CRMP2 hyperphosphorylation.
• This interaction offers new insights into the molecular pathways of Alzheimer's Disease.