TGFβ is part of a growth factor superfamily which modulates cell growth, differentiation, adhesion, migration, ECM synthesis and apoptosis (Massague, 1998; Siegel and Massague, 2003). Free TGFβ binds to its high affinity TGFβ receptor, a receptor serine/threonine kinase, inducing phosphorylation of Smad2/3 which subsequently forms a complex with Smad4 to translocate to the nucleus where it interacts with multiple co-activators and repressors generating distinct transcriptional responses.
Indeed, TGFβ signaling shows a remarkable cellular context dependency and apparent multifunctionality: e.g. TGFβ is able to inhibit cell proliferation in many epithelial cells but can also enhance proliferation in fibroblasts and cell growth in endothelial cells (Guasch et al., 2007; Xiao et al., 2012); it enhances stem cell pluripotency, but promotes differentiation in other cells (Park, 2011); in cancer development it suppresses pre-malignant cell proliferation, but at the same time promotes conversion to a metastatic phenotype (Chaudhury and Howe, 2009).
The TGFβ stimulation assay monitors the responsiveness of cells to TGFβ. Upon TGFβ stimulation short-term effects such as Smad2 phosphorylation and long-term effects such as cell proliferation can be analyzed. The assay will be described for murine keratinocytes, where TGFβ strongly inhibits cell proliferation, but both assays are applicable for other cell types as well.
Thanks for your further question/comment. It has been sent to the author(s) of this protocol. You will receive a notification once your question/comment is addressed again by the author(s).
Meanwhile, it would be great if you could help us to spread the word about Bio-protocol.