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Functional gap junctions in the schwann cell myelin sheath
R J Balice-Gordon1, L J Bone, S S Scherer
1Department of Neuroscience, The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA. rbaliceg@mail.med.upenn.edu
The Journal of Cell Biology
|August 29, 1998
Summary
Functional gap junctions in Schwann cells facilitate rapid molecule diffusion across the myelin sheath. These junctions, involving connexin32 and other connexins, are crucial for myelin function.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Schwann cells form the myelin sheath, a complex multilamellar structure.
- Distinct protein localizations exist within different myelin sheath domains.
- Functional gap junctions are present within the myelin sheath, enabling molecule diffusion.
Purpose of the Study:
- To investigate the presence and function of gap junctions within the Schwann cell myelin sheath.
- To identify the connexin proteins involved in these gap junctions.
- To understand the role of gap junctions in molecule diffusion across the myelin sheath.
Main Methods:
- Intracellular dye injection and video microscopy were employed.
- Analysis of myelinating Schwann cells from wild-type and connexin32-null mice.
- Assessment of radial diffusion of low molecular weight dyes.
Main Results:
- Functional gap junctions were identified in Schmidt-Lanterman incisures and paranodes.
- Connexin32 (Cx32) was found in these regions, but other connexins also participate.
- Radial diffusion was not impaired in connexin32-null mice, indicating alternative connexin involvement.
- A gap junction-mediated radial pathway offers a significantly faster diffusion route compared to the circumferential pathway.
Conclusions:
- Gap junctions are functionally present within the Schwann cell myelin sheath.
- Multiple connexins, not solely Cx32, form these gap junctions.
- Radial diffusion facilitated by gap junctions is vital for efficient transport within myelinating Schwann cells.