Actin and dynamin2 dynamics and interplay during clathrin-mediated endocytosis

Area of Science:

• Cell Biology
• Molecular Biology

Background:

• Clathrin-mediated endocytosis (CME) requires coordinated protein assembly at the plasma membrane.
• The precise mechanisms governing protein recruitment timing and stoichiometry during CME remain incompletely understood.

Purpose of the Study:

• To investigate the stoichiometry, dynamics, and functional interplay of dynamin2 with actin during CME.
• To elucidate the temporal regulation of protein recruitment in CME.

Main Methods:

• Utilized genome editing to express fluorescent fusion proteins at native levels.
• Employed live-cell imaging with single-molecule sensitivity to observe CME dynamics.
• Performed quantitative analyses of dynamin2 and actin interactions.

Main Results:

• Observed heterogeneous timing in the early phase of CME with transient dynamin2 recruitment (2-4 molecules).
• Demonstrated regular dynamin2 recruitment (∼26 molecules) during the final 20 s of CME, forming a complete ring.
• Found that actin assembly typically precedes and promotes dynamin2 recruitment during late CME stages.

Conclusions:

• Dynamin2 recruitment during CME is precisely regulated in terms of timing and quantity.
• Actin polymerization plays a crucial role in promoting and regulating dynamin2 recruitment during CME.
• These findings provide insights into the coordinated molecular events underlying endocytosis.