Tight junctions in Schwann cells of peripheral myelinated axons

• Published in: The Journal of cell biology 2005-05, Vol.169 (3), p.527-538
• Main Authors: Miyamoto, Tatsuo, Morita, Kazumasa, Takemoto, Daisuke, Takeuchi, Kosei, Kitano, Yuka, Miyakawa, Tsuyoshi, Nakayama, Kiyomi, Okamura, Yasushi, Sasaki, Hiroyuki, Miyachi, Yoshiki, Furuse, Mikio, Tsukita, Shoichiro
• Format: Article
• Language: English
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200501154

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.