Transforming Growth Factor (TGF) Superfamily

By: Jennifer Fries, BioFiles 2009, 4.5, 21.

The transforming growth factor-β (TGF-β) superfamily of cytokines include the structurally related subfamily of TGF-βs, the subfamily of bone morphogenic proteins (BMP), decapentaplegic (dpp) and Vg1, the subfamily of Mullerian inhibitory substances (MIS), and the subfamily of activins and inhibins.1,2 In general, individual members of this superfamily were originally purified and characterized with a specific functional assay, but most of these have broader biological activities that are particularly relevant in development. TGF-β superfamily members have a conserved set of six cysteine residues that form a rigid “cysteine knot’’ in the carboxyterminal region. They are all secreted as large propeptide molecules which then form homodimers (or sometimes heterodimers with certain other superfamily members). Because TGF-βs and BMPs receptors share close similarities, these two subfamilies are grouped together in this section.


Growth factors (purple and yellow) bind to receptors (blue and green) that protrude from a cell’s surface. Growth factors are one-way cells communicate with each other, and control the division of neighboring cells. When there are too many growth factors or their receptors, unchecked cell growth occurs which can lead to cancer.

Bone morphogenetic (BMP) induces ectopic bone formation, and plays an important role in the development of the viscera. Ligand binding to its receptor induces the formation of a complex in with the Type II BMP receptor phosphorylates and activates the Type I BMP receptor. The Type I BMP receptor then propagates the signal by phosphorylating a family of signal transducers, the Smad proteins. Currently, eight Smad proteins have been cloned (Smad 1-7 and Smad 9). Upon phosphorylation by BMP Type I receptor, Smad1 can interact with either Smad4 or Smad6. The Smad1-Smad6 complex is inactive; however, the Smad1-Smad4 complex triggers the expression of BMP responsive genes. The ratio between Smad4 and Smad6 in the cell can modulate the strength of the signal transduced by BMP.

References:
Fujii, M., et al., Roles of bone morphogenetic protein type I receptors and Smad proteins in osteoblast and chrondoblast differentiation. Mol. Biol. Cell., 10, 3801-3813 (1999). Kawabata, M., et al., Signal transduction by bone morphogenetic proteins. Cytokine Growth Factor Rev., 9, 49-61 (1998).

back to top

Transforming Growth Factor-α (TGF-α)

Product Description Source Recombinant Host Physical Form Assay Cell Type Affected Cat. No.
Transforming Growth Factor-α human Escherichia coli powder The biological activity is measured by its ability to stimulate 3H-thymidine incorpation into BALB/c 3T3 cells. endothelial cell mammary epithelial cell fibroblast ovary cell glial cell prostate cell myeloma cell vascular endothelial cell granuloma cell chrondrocyte HeLa cell T7924-.1MG

back to top

Transforming Growth Factor-β1 (TGF-β1)

Product Description Source Recombinant Host Physical Form Assay Cell Type Affected Cat. No.
Transforming Growth Factor-β1 from human platelets - lyophilized powder The biological activity is measured by its ability to inhibit the IL-4-dependent proliferation of mouse HT-2 cells. mesenchymal-derived cell T1654-1UG
Transforming Growth Factor-β1 from porcine platelets - powder The biological activity is measured by its ability to inhibit the IL-4-dependent proliferation of mouse HT-2 cells.   T5050-1UG
Transforming Growth Factor-β1 human CHO cells powder The biological activity of TGF-β1 is measured in culture by inhibition of mouse IL-4- dependent proliferation of mouse HT-2 cells.   T7039-2UG

back to top

Materials

     

References

  1. Gitelman, S., and Derynck, R., Transforming growth factor β (TGF-β), in Guidebook to Cytokines and Their Receptors, Nicola, N., ed., Oxford Press (New York, NY: 1994), pp. 223-226.
  2. O’Kane, S., and Ferguson, M., Transforming growth factor-βs and wound healing. Int. J. Biochem. Cell Biol., 29, 63-78 (1997).

back to top

Related Links