Expression of MAP kinases and connexins in the differentiation of rat mammary epithelial cells.
Gap junctional intercellular communication (GJIC) is involved in the regulation of many cellular processes. MAP kinases are known to affect GJIC and phosphorylation of connexin (Cx). MAP kinases can also be a regulator of cell proliferation and growth. This study was undertaken to show the relevance between expression patterns of Cxs and MAP kinases in rat mammary epithelial cells (RMECs). In order to characterize the RMECs, they were stained with Peanut lectin, which indicates most alveolar epithelial cells, and Thy-1.1 was used as a marker of luminal epithelial cells or myoepithelial cells, respectively. We studied the expression patterns of major gap junction proteins, Cx26, 32, and 43 in RMECs. Western blot analysis demonstrated that Cx26 gradually decreased from day 2, while Cx32 was expressed constantly from day 1 to 14. Cx43 dramatically increased on day 5 and decreased thereafter. The expression patterns and phosphorylation of ERK1/2 and JNK were similar to Cx43, but expression of p38 was like that of Cx32. These results showed that the MAP kinases that comprise ERK1/2, p38, and JNK were involved in regulation of Cxs. Our data suggests that GJIC plays an important role during rat mammary differentiation and that MAP kinases may be closely related functionally to regulate the gap junction.
Seo
Min-Soo
MS
Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Korea.
Park
Joon-Suk
JS
Yang
Se-Ran
SR
Park
Ki-Su
KS
Hong
In-Sun
IS
Jo
Eun-Hye
EH
Kang
Kyung-Sun
KS
Lee
Yong-Soon
YS
D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D008321:Mammary Glands, Animal / Q000166:cytology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D017630:Connexins; D020928:Mitogen-Activated Protein Kinases