A dynamic partitioning mechanism polarizes membrane protein distribution

Area of Science:

• Cell Biology
• Biophysics
• Biochemistry

Background:

• The plasma membrane is central to signal transduction, controlling cell polarity and migration.
• Mechanisms driving dynamic protein compartmentalization and symmetry breaking in the plasma membrane are not well understood.

Approach:

• Utilized multimodal live-cell imaging and selective photoconversion-based protein tracking.
• Performed single-molecule measurements and developed a reaction-diffusion model.
• Employed optogenetic recruitment of peptides in Dictyostelium and mammalian neutrophil cells.

Key Points:

• Lipid-anchored proteins were unexpectedly depleted from activated signaling domains, unlike peripheral proteins.
• This depletion was not due to dissociation, translocation, vesicular trafficking, or cytoskeletal constraints.
• Evidence suggests proteins dynamically partition into distinct membrane domains, supported by varied diffusion profiles.
• Simulations confirm dynamic partitioning generates asymmetric wave patterns.

Conclusions:

• Introduced 'dynamic partitioning' as a new mechanism for plasma membrane organization.
• This mechanism accounts for large-scale compartmentalization of membrane proteins in physiological processes.
• Demonstrated optogenetic induction of spatiotemporal partitioning to create polarized patterns.