TGFβ and BMPs signaling pathways.
(A) In the canonical pathway,
TGFβ and BMPs bind to their respective receptors resulting in
phosphorylation of Smad2/3 or Smad1/5/9, respectively. Common Smad4
binds to both Smad complexes and facilitates translocation to the
nucleus, thereby activating transcription. (B) Alternatively, after
receptor binding, the signal can be transduced via several noncanonical
pathways including nitogen-activated protein kinase (MAPK), phosphoinositide
3-kinase (PI3K), and c-Jun N-terminal kinase (JNK), also resulting
in gene transcription. Akt, protein kinase B; CRE, cyclic adenosine-monophosphate
response element; ERK, extracellular signal-regulated kinases; MEK,
mitogen-activated protein kinase kinase; mTOR, mammalian target of
rapamycin; SBE, Smad binding element; TAK1, TGFβ-activated kinase
1; TAB1, TAK-1 binding protein 1. Figure created using artwork provided
by Somesault1824, licensed under a Creative Commons License (CC BY-NC-SA
4.0).