The transforming growth factor beta (TGFB) signaling pathway is involved in many cellular processes in both the adult organism and the developing embryo including cell growth, cell differentiation, cell migration, apoptosis, cellular homeostasis and other cellular functions. The TGFB signaling pathways are conserved. In spite of the wide range of cellular processes that the TGFβ signaling pathway regulates, the process is relatively simple. TGFβ superfamily ligands bind to a type II receptor, which recruits and phosphorylates a type I receptor. The type I receptor then phosphorylates receptor-regulated SMADs (R-SMADs) which can now bind the coSMAD SMAD4. R-SMAD/coSMAD complexes accumulate in the nucleus where they act as transcription factors and participate in the regulation of target gene expression.
Follistatin also known as activin-binding protein is a protein that in humans is encoded by the FST gene. Follistatin is an autocrine glycoprotein that is expressed in nearly all tissues of higher animals.
The activin A receptor also known as ACVR1C or ALK-7 is a protein that in humans is encoded by the ACVR1C gene. ACVR1C is a type I receptor for the TGFB family of signaling molecules.
Activin receptor type-1B is a protein that in humans is encoded by the ACVR1B gene.
Activin receptor type-2A is a protein that in humans is encoded by the ACVR2A gene. ACVR2A is an activin type 2 receptor.
The activin type 2 receptors belong to a larger TGF-beta receptor family and modulate signals for transforming growth factor beta ligands. These receptors are involved in a host of physiological processes including, growth, cell differentiation, homeostasis, osteogenesis, apoptosis and many other functions. There are two activin type two receptors: ACVR2A and ACVR2B.
Activin receptor type-2B is a protein that in humans is encoded by the ACVR2B gene. ACVR2B is an activin type 2 receptor.
Betaglycan also known as Transforming growth factor beta receptor III (TGFBR3), is a cell-surface chondroitin sulfate / heparan sulfate proteoglycan >300 kDa in molecular weight. Betaglycan binds to various members of the TGF-beta superfamily of ligands via its core protein, and bFGF via its heparan sulfate chains. TGFBR3 is the most widely expressed type of TGF-beta receptor. Its affinity towards all individual isoforms of TGF-beta is similarly high and therefore it plays an important role as a coreceptor mediating the binding of TGF-beta to its other receptors - specifically TGFBR2. The intrinsic kinase activity of this receptor has not yet been described. In regard of TGF-beta signalling it is generally considered a non-signaling receptor or a coreceptor. By binding to various member of the TGF-beta superfamily at the cell surface it acts as a reservoir of TGF-beta.
The transforming growth factor beta (TGF-β) superfamily is a large group of structurally related cell regulatory proteins that was named after its first member, TGF-β1, originally described in 1983. They interact with TGF-beta receptors.
Integrin alpha-1 also CD49a is an integrin alpha subunit encoded in humans by the gene ITGA1. It makes up half of the α1β1 integrin duplex.
Inhibin, beta A, also known as INHBA, is a protein which in humans is encoded by the INHBA gene. INHBA is a subunit of both activin and inhibin, two closely related glycoproteins with opposing biological effects.
Inhibin, alpha, also known as INHA, is a protein which in humans is encoded by the INHA gene.
Transforming growth factor beta-3 is a protein that in humans is encoded by the TGFB3 gene.
Integrin beta-6 is a protein that in humans is encoded by the ITGB6 gene. It is the β6 subunit of the integrin αvβ6. Integrins are αβ heterodimeric glycoproteins which span the cell’s membrane, integrating the outside and inside of the cell. Integrins bind to specific extracellular proteins in the extracellular matrix or on other cells and subsequently transduce signals intracellularly to affect cell behaviour. One α and one β subunit associate non-covalently to form 24 unique integrins found in mammals. While some β integrin subunits partner with multiple α subunits, β6 associates exclusively with the αv subunit. Thus, the function of ITGB6 is entirely associated with the integrin αvβ6.
Beta-microseminoprotein is a protein that in humans is encoded by the MSMB gene. For historical reasons, the scientific literature may also refer to this protein as Prostate secretory protein 94 (PSP94), microseminoprotein (MSP), microseminoprotein-beta (MSMB), beta-inhibitin, prostatic inhibin peptide (PIP), and inhibitin like material (ILM).
Follistatin-related protein 3 is a protein that in humans is encoded by the FSTL3 gene.
Early placenta insulin-like peptide is a protein that in humans is encoded by the INSL4 gene.
Inhibin, beta B, also known as INHBB, is a protein which in humans is encoded by the INHBB gene. INHBB is a subunit of both activin and inhibin, two closely related glycoproteins with opposing biological effects.
Luteinizing hormone subunit beta also known as lutropin subunit beta or LHβ is a polypeptide that in association with an alpha subunit common to all gonadotropin hormones forms the reproductive signaling molecule luteinizing hormone. In humans it is encoded by the LHB gene.
Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. Identified in 1986, activin enhances FSH biosynthesis and secretion, and participates in the regulation of the menstrual cycle. Many other functions have been found to be exerted by activin, including roles in cell proliferation, differentiation, apoptosis, metabolism, homeostasis, immune response, wound repair, and endocrine function. Conversely, inhibin downregulates FSH synthesis and inhibits FSH secretion. The existence of inhibin was hypothesized as early as 1916; however, it was not demonstrated to exist until Neena Schwartz and Cornelia Channing's work in the mid-1970s, after which both proteins were molecularly characterized ten years later.
