Distribution of the cadherin-catenin complex in normal human thyroid epithelium and a thyroid carcinoma cell line.
E-cadherin is the major cell-cell adhesion molecule expressed by epithelial cells. Cadherins form a complex with three cytoplasmic proteins, alpha-, beta-, and gamma-catenin, and the interaction between them is crucial for anchoring the actin cytoskeleton to the intercellular adherens junctions. The invasive behavior of cancer cells has been attributed to a dysfunction of these molecules. In this study, we examined the distribution of the cadherin-catenin complex in a Chinese human thyroid cancer cell line, CGTH W-2, compared with that in normal human thyroid epithelial cells. In the normal cells, using immunofluorescence staining, E-cadherin and alpha-, beta-, and gammm-catenin were found to be localized at the intercellular junction and appeared as 135, 102, 90, and 80 kD proteins on Western blots. In CGTH W-2 cells, no E-cadherin and gamma-catenin immunoreactivity was detected by immunofluorescence or Western blotting; alpha- and beta-catenin were detected as 102 and 90 kD proteins on blots but gave a diffuse cytoplasmic immunofluorescence staining pattern in most cells, while beta-catenin was also distributed throughout the cytoplasm in most cells but was found at the cell junction in some, where it colocalized with alpha-actinin. The present data indicate that the loss of cell adhesiveness in these cancer cells may be due to incomplete assembly of the cadherin-catenin complex at the cell junction. However, this defect did not affect the linkage of actin bundles to vinculin-enriched intercellular junctions.
Huang
S H
SH
Department of Surgery, College of Medicine, National Taiwan University, Taipei, Republic of China.
Wu
J C
JC
Chang
K J
KJ
Liaw
K Y
KY
Wang
S M
SM
D000185:Actinin / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D015820:Cadherins / Q000032:analysis*; D002448:Cell Adhesion; D002460:Cell Line; D003593:Cytoplasm / Q000737:chemistry; D003598:Cytoskeletal Proteins / Q000032:analysis* / Q000378:metabolism; D051180:Desmoplakins; D004847:Epithelial Cells / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000737:chemistry; D008856:Microscopy, Fluorescence; D013961:Thyroid Gland / Q000737:chemistry*; D013964:Thyroid Neoplasms / Q000737:chemistry*; D015534:Trans-Activators; D014407:Tumor Cells, Cultured; D016596:Vinculin / Q000378:metabolism; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin
D000199:Actins; C495273:CTNNA1 protein, human; C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; C495292:JUP protein, human; D015534:Trans-Activators; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin; D000185:Actinin; D016596:Vinculin