Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19-deficient mice.
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.
Miyamoto
Tatsuo
T
Department of Cell Biology, Graduate School of Medicine, Kyoto University, Japan.
Morita
Kazumasa
K
Takemoto
Daisuke
D
Takeuchi
Kosei
K
Kitano
Yuka
Y
Miyakawa
Tsuyoshi
T
Nakayama
Kiyomi
K
Okamura
Yasushi
Y
Sasaki
Hiroyuki
H
Miyachi
Yoshiki
Y
Furuse
Mikio
M
Tsukita
Shoichiro
S
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
D057167:Claudins; C502666:Cldn19 protein, mouse; D008565:Membrane Proteins