Live-cell atomic force microscopy nanoprofiling reveals protease-responsive membrane protein dynamics and...

Area of Science:

• Cellular Biology
• Biophysics
• Nanotechnology

Background:

• Cell membranes, composed of phospholipid-protein interfaces, are crucial for cellular recognition and communication.
• Real-time nanoscale observation of native membrane proteins in live cells presents significant technical challenges.

Purpose of the Study:

• To characterize the surface properties of live cells using atomic force microscopy (AFM).
• To investigate how nanoscale surface morphology relates to cell identity, functional state, and malignancy.

Main Methods:

• Employed atomic force microscopy (AFM) to characterize the surface properties of live HeLa cells.
• Utilized mild trypsin digestion and chemical fixation to assess their impact on membrane properties.
• Performed comparative AFM imaging across four distinct cell lines (HeLa, MCF-7, NIH-3T3, and one unspecified).

Main Results:

• Mild trypsin digestion significantly reduced surface roughness (Rq: ~150 nm to ~120 nm) and adhesion force (~27 pN to ~20 pN) in live HeLa cells.
• Chemical fixation obscured these dynamic changes observed with trypsin digestion.
• Distinct nanoscale topographies were observed across cell lines: MCF-7 cancer cells showed the highest roughness (Rq = 212 nm), while NIH-3T3 fibroblasts had smoother morphology (Rq = 172 nm).

Conclusions:

• Nanoscale surface morphology encodes critical information about cell identity, functional state, and malignancy.
• Increased surface roughness correlates with complex membrane protein organization.
• Live-cell AFM provides a powerful platform for decoding membrane protein dynamics and cell-type-specific surface codes, with potential applications in various biological and medical fields.