Vectorial TGFbeta signaling in polarized intestinal epithelial cells.
Vectorial TGFbeta signaling in polarized intestinal epithelial cells.
复制标题
极化肠上皮细胞中的矢量 TGFbeta 信号传导。
DOI：
10.1002/jcp.22135
复制
发表时间：
2010
影响因子：
5.6
通讯作者：
Barnard,JohnA
中科院分区：
文献类型：
--
作者：
Yakovich,AdamJ;Huang,Qin;Du,Jianguo;Jiang,Bo;Barnard,JohnA
Polarized gastrointestinal epithelial cells form tight junctions that spatially separate apical and basolateral cell membrane domains. These domains harbor functionally distinct proteins that contribute to cellular homeostasis and morphogenesis. Transforming growth factor β (TGFβ) is a critical regulator of gastrointestinal epithelial cell growth and differentiation. Functional assays of vectorial TGFβ signaling and immunofluorescence techniques were used to determine the localization of TGFβ receptors and ligand secretion in polarizing Caco‐2 cells, a colon cancer cell line. Results were compared to the nontransformed MDCK cell line. In both Caco‐2 and MDCK cells, addition of TGFβ1 to the basolateral medium resulted in phosphorylation of Smad2. No phosphorylation was observed when TGFβ1 was added to the apical chamber, indicating that receptor signaling is localized at the basolateral membrane. In support of this, immunofluorescence and biotinylation assays show receptor localization along the basolateral membrane. Secretion of TGFβ1 from MDCK and Caco‐2 cells into the apical or basolateral medium was measured by ELISA. Interestingly, secretion was exclusively apical in the nontransformed MDCK line and basolateral in transformed Caco‐2 cells. Collectively, these results show basolateral domain specificity in localization of the TGFβ receptor signaling apparatus. These observations have important implications for understanding the biology of TGFβ in polarized epithelia, including elements of communication between epithelial and mesenchymal layers, and will prove useful in the design of therapeutics that target TGFβ function. J. Cell. Physiol. 224: 398–404, 2010. © 2010 Wiley‐Liss, Inc.
