Internalization of large double-membrane intercellular vesicles by a clathrin-dependent endocytic process.

Area of Science:

• Cell Biology
• Molecular Biology
• Endocytosis

Background:

• Clathrin is known for vesicle endocytosis and internalization of large particles.
• Gap junctions (GJs) mediate cell-to-cell communication via channel complexes.

Purpose of the Study:

• To investigate a novel clathrin-dependent endocytic process involving gap junctions.
• To characterize the internalization and degradation of gap junction plaques.

Main Methods:

• Microscopy and biochemical assays to identify clathrin-dependent machinery.
• Analysis of clathrin, Dab2, dynamin, myosin-VI, and actin involvement.
• Tracking of internalized gap junction vesicles and their degradation pathways.

Main Results:

• Discovered clathrin-dependent internalization of entire gap junction plaques as double-membrane vesicles (annular gap junctions, AGJs).
• Demonstrated involvement of clathrin, Dab2, dynamin, myosin-VI, and actin in AGJ internalization and movement.
• Showed that AGJs are subsequently degraded via endo/lysosomal pathways.

Conclusions:

• Gap junction plaques are internalized via a clathrin-dependent mechanism.
• This process expands the known functions of clathrin beyond traditional endocytosis.
• Identified key molecular players in the internalization and degradation of intercellular vesicles.