MIT chemists have uncovered a fascinating new insight into the role of cell membranes, challenging long-held beliefs about their function. The study, led by Professor Gabriela Schlau-Cohen, reveals that cell membranes not only provide structure and protection but also actively influence the behavior of embedded protein receptors, particularly the Epidermal Growth Factor Receptor (EGFR).
The research demonstrates that altering the composition of the cell membrane can significantly impact the function of EGFR, a receptor crucial for controlling cell growth. By increasing the concentration of negatively charged lipids in the membrane, the study found that EGFR can be locked into an overactive state, promoting uncontrolled cell proliferation, a hallmark of cancer.
This discovery challenges the traditional view of cell membranes as mere scaffolds, suggesting that membrane lipids play a dynamic role in receptor function. Schlau-Cohen's team used nanodiscs, self-assembling membranes that mimic the cell membrane, to study the receptor's behavior. They employed single-molecule FRET (fluorescence resonance energy transfer) to measure the distance between different parts of the protein, revealing how the receptor's shape changes under various conditions.
The findings have profound implications for cancer research. High levels of negatively charged lipids in cancer cells may contribute to their uncontrolled growth by keeping EGFR in an active state, regardless of whether the ligand (EGF) is bound or not. This mechanism could be a potential target for new cancer treatments, where neutralizing the negative charge might turn down EGFR signaling, thus inhibiting tumor growth.
Furthermore, the study explored the role of cholesterol in EGFR function. Elevated cholesterol levels in the membrane made the membranes more rigid, suppressing EGFR signaling. This suggests that cholesterol may also play a crucial role in regulating receptor activity and could be a target for therapeutic intervention.
In conclusion, this MIT study highlights the dynamic nature of cell membranes and their profound impact on receptor function, particularly in cancer biology. It opens up exciting avenues for research and potential therapeutic strategies, emphasizing the importance of understanding the intricate relationship between membrane composition and receptor behavior.
