Behavior of tight-junction, adherens-junction and cell polarity proteins during HNF-4alpha-induced epithelial polarization.
We previously reported that expression of tight-junction molecules occludin, claudin-6 and claudin-7, as well as establishment of epithelial polarity, was triggered in mouse F9 cells expressing hepatocyte nuclear factor (HNF)-4alpha [H. Chiba, T. Gotoh, T. Kojima, S. Satohisa, K. Kikuchi, M. Osanai, N. Sawada. Hepatocyte nuclear factor (HNF)-4alpha triggers formation of functional tight junctions and establishment of polarized epithelial morphology in F9 embryonal carcinoma cells, Exp. Cell Res. 286 (2003) 288-297]. Using these cells, we examined in the present study behavior of tight-junction, adherens-junction and cell polarity proteins and elucidated the molecular mechanism behind HNF-4alpha-initiated junction formation and epithelial polarization. We herein show that not only ZO-1 and ZO-2, but also ZO-3, junctional adhesion molecule (JAM)-B, JAM-C and cell polarity proteins PAR-3, PAR-6 and atypical protein kinase C (aPKC) accumulate at primordial adherens junctions in undifferentiated F9 cells. In contrast, CRB3, Pals1 and PATJ appeared to exhibit distinct subcellular localization in immature cells. Induced expression of HNF-4alpha led to translocation of these tight-junction and cell polarity proteins to beltlike tight junctions, where occludin, claudin-6 and claudin-7 were assembled, in differentiated cells. Interestingly, PAR-6, aPKC, CRB3 and Pals1, but not PAR-3 or PATJ, were also concentrated on the apical membranes in differentiated cells. These findings indicate that HNF-4alpha provokes not only expression of tight-junction adhesion molecules, but also modulation of subcellular distribution of junction and cell polarity proteins, resulting in junction formation and epithelial polarization.
Satohisa
Seiro
S
Department of Pathology, Sapporo Medical University School of Medicine, South-1, West-17, Chuo-ku, Sapporo 060-8556, Japan.
Chiba
Hideki
H
Osanai
Makoto
M
Ohno
Shigeo
S
Kojima
Takashi
T
Saito
Tsuyoshi
T
Sawada
Norimasa
N
D022005:Adherens Junctions / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D016764:Cell Polarity / Q000187:drug effects; D057167:Claudins; D004268:DNA-Binding Proteins / Q000494:pharmacology*; D004847:Epithelial Cells / Q000737:chemistry / Q000502:physiology*; D015870:Gene Expression; D051557:Hepatocyte Nuclear Factor 4; D015151:Immunoblotting; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D010750:Phosphoproteins / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019108:Tight Junctions / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000494:pharmacology*
C473255:CLDN7 protein, human; D057167:Claudins; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D008565:Membrane Proteins; D010750:Phosphoproteins; D014157:Transcription Factors; C122101:claudin 6