Signal integration by lipid-mediated spatial cross talk between Ras nanoclusters

Area of Science:

• Cell Biology
• Biochemistry
• Membrane Biophysics

Background:

• Ras GTPases are crucial for cell signaling, forming transient nanoclusters on the plasma membrane.
• The lipid composition and sorting mechanisms within these Ras nanoclusters remain largely uncharacterized.

Purpose of the Study:

• To investigate the lipid composition of Ras nanoclusters.
• To understand how lipid composition contributes to isoform-specific Ras signaling and membrane organization.

Main Methods:

• High-resolution spatial mapping of Ras nanoclusters.
• Computational modeling of membrane dynamics.
• Experimental manipulation of phosphatidylserine levels.

Main Results:

• Ras nanoclusters exhibit distinct lipid compositions, reflecting isoform-selective lipid sorting.
• Phosphatidylserine is essential for K-Ras nanocluster structure and influences H-Ras and K-Ras segregation.
• Ras nanoclusters mediate remote communication, with H-Ras impacting K-Ras nanocluster assembly via phosphatidylserine dynamics.

Conclusions:

• Phosphatidylserine plays a critical role in maintaining the lateral segregation of distinct lipid assemblies on the plasma membrane.
• Ras nanocluster formation influences phosphatidylserine organization, enabling lipid-mediated communication and signal integration.