The RhoA-Rok-myosin II pathway is involved in extracellular matrix-mediated regulation of prolactin signaling in mammary epithelial cells.
Bottom Line: Under these culture conditions, the RhoA pathway is activated, leading to downregulation of prolactin receptor expression and reduced prolactin signaling.In addition, inhibition of myosin II ATPase activity by blebbistatin also exerts a beneficial effect on prolactin receptor expression and prolactin signaling, suggesting that tension exerted by the collagen substratum, in collaboration with the RhoA-Rok-myosin II pathway, contributes to the failure of prolactin signaling.They display high levels of RhoA activity and are inefficient in prolactin signaling, stressing the importance of matrix stiffness in signal transduction.
Affiliation: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan, ROC.Show MeSH
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Mentions: Our results show that prolactin signaling in MECs cultured on the soft BM hydrogel is more efficient than signaling in cells cultured on the rigid surface of collagen I-coated plastic. These culture conditions differ in both matrix rigidity and composition. Since laminin is the major component of BM and is essential for prolactin signaling, we examined prolactin signaling in MECs cultured on laminin-coated plastic, which has about the same rigidity as collagen I-coated dishes. This would help to show whether matrix stiffness affects prolactin signaling. Similar to MECs cultured on 2D collagen I, cells on 2D laminin formed monolayers, and exhibited higher RhoA activity than those cultured on 3D BM (Fig. 8A,B).
Affiliation: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan, ROC.