The transforming growth factor-beta system, a complex pattern of cross-reactive ligands and receptors.
A new homodimer form of transforming growth factor-beta (TGF-beta), TGF-beta 2, has been identified in porcine blood platelets. TGF-beta 2 is homologous to ordinary TGF-beta (TGF-beta 1), which is also present in platelets. TGF-beta 1.2, a heterodimer containing one TGF-beta 1 chain and one TGF-beta 2 chain, has also been isolated. TGF-beta 1 and TGF-beta 2 interact differently with a family of receptors in target cells. A 280 kd receptor displays high affinity for both TGF-beta 1 and TGF-beta 2. Occupancy of this receptor by TGF-beta 1 or TGF-beta 2 correlates with the ability of these TGF-beta s to inhibit cell proliferation. In contrast, 65 kd and 85 kd receptors have high affinity for TGF-beta 1 but lower affinity for TGF-beta 2. The existence of distinct forms of TGF-beta that interact differently with a family of TGF-beta receptors could provide flexibility to the regulation of tissue growth and differentiation by the TGF-beta system.
D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003429:Cross Reactions; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D010455:Peptides / Q000032:analysis / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta; D013552:Swine; D015291:Transforming Growth Factors
D010455:Peptides; D011956:Receptors, Cell Surface; D018125:Receptors, Transforming Growth Factor beta; D015291:Transforming Growth Factors; D004247:DNA