title: Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19-deficient mice.
abstract: 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.
authors.affiliation: Department of Cell Biology, Graduate School of Medicine, Kyoto University, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Morita
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takemoto
authors.forename: Kosei
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kitano
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Miyakawa
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Nakayama
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okamura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Miyachi
authors.forename: Mikio
authors.initials: M
authors.lastname: Furuse
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsukita
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D057167:Claudins; D005260:Female; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009186:Myelin Sheath / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D009413:Nerve Fibers, Myelinated / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D009431:Neural Conduction / Q000235:genetics; D010525:Peripheral Nerves / Q000002:abnormalities* / Q000378:metabolism / Q000648:ultrastructure; D011901:Ranvier's Nodes / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D012583:Schwann Cells / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D019108:Tight Junctions / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure
chemical_list: D057167:Claudins; C502666:Cldn19 protein, mouse; D008565:Membrane Proteins