A F₄₂₀-dependent Single Domain Chemogenetic Tool for Protein De-dimerization

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Protein-protein interactions (PPIs) are crucial for cellular functions.
• Chemogenetic tools controlling PPIs are valuable for research and clinical applications.
• Existing methods primarily induce protein association, with limited options for dissociation.

Purpose of the Study:

• To develop a novel bioorthogonal chemogenetic tool for controlled protein complex dissociation.
• To exploit the F420-dependent dissociation of mycobacterial MSMEG_2027 as a monomerization switch.
• To demonstrate the tool's utility in regulating signaling pathways in human cells.

Main Methods:

• X-ray crystallography to determine the structure of MSMEG_2027 and its interaction with F420.
• Fusion of MSMEG_2027 to a chimeric fibroblast growth factor receptor 1 (FGFR1) tyrosine kinase.
• Application in human cells to modulate MAPK/ERK signaling.

Main Results:

• MSMEG_2027 forms a unique domain-swapped dimer that dissociates upon F420 binding.
• F420 binding induces N-terminal helix rearrangement, leading to dimer dissolution.
• The tool successfully induced and released MAPK/ERK signaling downstream of FGFR1 in human cells.

Conclusions:

• MSMEG_2027 serves as a novel, F420-dependent chemogenetic de-homodimerization switch.
• This single-domain tool offers a stoichiometric and bioorthogonal mechanism for controlling protein complexes in situ.
• The approach provides a new avenue for investigating protein interactions within living systems.