Labeling proteins on live mammalian cells using click chemistry

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Cell-surface protein labeling is crucial for studying cellular processes.
• Existing methods may lack specificity or efficiency in living mammalian cells.

Purpose of the Study:

• To develop a rapid and site-specific protocol for labeling cell-surface proteins in living mammalian cells.
• To utilize click chemistry reactions for efficient dye conjugation to proteins of interest.

Main Methods:

• Employing genetic code expansion to introduce noncanonical amino acids (ncAAs) bearing alkynes or alkenes at specific sites via Amber stop codon suppression.
• Utilizing orthogonal aminoacyl-tRNA synthetase/tRNA pairs for site-specific ncAA incorporation in mammalian cells.
• Applying strain-promoted alkyne-azide cycloaddition (SPAAC) and strain-promoted inverse-electron-demand Diels-Alder cycloaddition (SPIEDAC) for dye conjugation.

Main Results:

• Successfully demonstrated site-specific labeling of the insulin receptor in living mammalian cells.
• Established a protocol adaptable for various noncanonical amino acids and commercially available dyes.
• Characterized optimal conditions and limitations for surface labeling in live cells.

Conclusions:

• The developed click chemistry protocol enables rapid and specific cell-surface protein labeling in living mammalian cells.
• This method offers a versatile tool for biological research, facilitating the study of cell surface dynamics and interactions.