Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19-deficient mice
Miyamoto, T.; Morita, K.; Takemoto, D.; Takeuchi, K.; Kitano, Y.; Miyakawa, T.; Nakayama, K.; Okamura, Y.; Sasaki, H.; Miyachi, Y.; Furuse, M.; Tsukita, S.
Journal of Cell Biology 169(3): 527-538
2005
ISSN/ISBN: 0021-9525 PMID: 15883201 DOI: 10.1083/jcb.200501154
Accession: 012694446
Tight junction (TJ)-like structures have been reported in Schwann cells, but their molecular composition and physiological function remain elusive. We found that claudin-19, a novel member of the claudin family (TJ adhesion molecules in epithelia), constituted these structures. Claudin-19-deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits. Electrophysiological analyses showed that the claudin-19 deficiency affected the nerve conduction of peripheral myelinated fibers. Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons. These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological "sealing" function of Schwann cells.