Claudin-19 (green) helps form tight junction structures that seal PNS myelin sheaths.
Tight junction-like structures run along myelin sheaths in both the central and peripheral nervous systems (CNS and PNS), but have only been functionally characterized in the CNS. Miyamoto et al. (
page 527) find evidence that these structures work as true tight junctions to seal off the myelin sheath and are required for proper neural conductance in the Schwann cells of the PNS.Claudin proteins are major cell adhesion molecules in tight junctions. Mutations in claudin-11 compromise the CNS, but leave the PNS untouched, begging the question as to whether the morphologically similar structures in the PNS act as tight junctions and if so whether a claudin family member is involved
Miyamoto et al. went looking for a claudin family member expressed in the PNS. Claudin-19 fit the bill. Mice lacking functional claudin-19...
