|
|
|
|
|
|
|
||
J. Cell Biol.,
Volume 143, Number 2, October 19, 1998 391-401
§
* Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan; Three integral membrane proteins, clau-
din-1, -2, and occludin, are known to be components of
tight junction (TJ) strands. To examine their ability to
form TJ strands, their cDNAs were introduced into
mouse L fibroblasts lacking TJs. Immunofluorescence microscopy revealed that both FLAG-tagged claudin-1
and -2 were highly concentrated at cell contact sites as
planes through a homophilic interaction. In freeze-fracture replicas of these contact sites, well-developed networks of strands were identified that were similar to TJ
strand networks in situ and were specifically labeled
with anti-FLAG mAb. In glutaraldehyde-fixed samples, claudin-1-induced strands were largely associated
with the protoplasmic (P) face as mostly continuous
structures, whereas claudin-2-induced strands were discontinuous at the P face with complementary grooves
at the extracellular (E) face which were occupied by
chains of particles. Although occludin was also concentrated at cell contact sites as dots through its homophilic interaction, freeze-fracture replicas identified
only a small number of short strands that were labeled with anti-occludin mAb. However, when occludin was
cotransfected with claudin-1, it was concentrated at cell
contact sites as planes to be incorporated into well-
developed claudin-1-based strands. These findings suggested that claudin-1 and -2 are mainly responsible for
TJ strand formation, and that occludin is an accessory
protein in some function of TJ strands.
Department of Molecular
Cell Biology, Institute of DNA Medicine, The Jikei University School of Medicine, Nishi-Shinbashi, Minato-ku, Tokyo 105, Japan; § Laboratory of Cell Biology, Kan Research Institute Inc., Minami-Kaneda, Suita, Osaka 564, Japan; and Department of
Anatomy, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
