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The structure and permeability of isolated hepatocyte gap junctions
Cold Spring Harbor Symposia on Quantitative Biology
|January 1, 1976
Summary
The ultrastructure of gap junctions, composed of connexons, reveals a hexagonal lattice. Changes in lattice condensation may relate to junctional permeability regulation, though further research is needed.
Area of Science:
- Cell biology
- Biophysics
Background:
- Gap junctions mediate direct cell-to-cell communication.
- Their ultrastructure, visualized by electron microscopy, involves connexons spanning intercellular gaps.
Purpose of the Study:
- To elucidate the structural organization of gap junctions and connexons.
- To investigate factors influencing connexon lattice arrangement and potential implications for permeability.
Main Methods:
- Electron microscopy (in situ and isolated preparations).
- X-ray diffraction experiments.
Main Results:
- Gap junctions are formed by connexons, subunits arranged in a hexagonal lattice.
- Lattice condensation increases as junctions become uncoupled, suggesting a link to permeability.
- Connexons span the junctional membranes, implying a role in cytoplasmic-to-cytoplasmic transport.
Conclusions:
- Connexons are key structural components of gap junctions, forming intercellular channels.
- The regulation of connexon lattice structure may be involved in controlling junctional permeability.
- Further investigation into protein-protein interactions within and between connexons is warranted.