ASAP-ID: Proximity Labelling With Small Tags

Area of Science:

• Cell biology
• Molecular biology
• Biochemistry

Background:

• Biotinylation-based proximity labeling is crucial for identifying protein-protein interactions.
• Current methods often require fusing target proteins with enzymes, risking disruption of native function.

Purpose of the Study:

• To develop a proximity labeling method that minimizes steric impact and enhances flexibility.
• To introduce Antibody and Small-tag Assembly on Proteins for Interaction Detection (ASAP-ID) for improved protein interaction studies.

Main Methods:

• ASAP-ID utilizes a bipartite system where target proteins fuse to a peptide antigen, recruiting enzyme-fused antibodies.
• The method was tested using SunTag and MoonTag systems for labeling human Lamin A.
• ASAP-ID was applied in cis (ASAP-ID^IC) and trans (ASAP-ID^IT) configurations.

Main Results:

• ASAP-ID successfully labeled human Lamin A in cells.
• ASAP-ID^IT identified over 448 known and novel Lamin A interactors.
• ASAP-ID^IT revealed distinct interactome changes in ALS-mutant profilin 1, correlating with aggregation propensity and cellular location.

Conclusions:

• ASAP-ID is a versatile and less invasive tool for proximity labeling.
• The method enables the discovery of protein interactors and the study of interactome alterations in disease models.
• ASAP-ID provides insights into subtle differences in protein interactions and cellular localization.