Question

Please describe four essential components of TGFb signaling pathway in terms of gene name and function under normal and cancer conditions as a table summary

Answer 1

TGF - beta signaling --- Serine / threonine receptors transduce signals for the TGF b family . These receptors are single pass trans -membrane proteins with a serine/ threonine kinase domain on the cytosolic end . There are two classes of these serine / threonine kinase receptors - type I and type II

The TGF b superfamily consists of a large number of structurally related , secretory , dimeric protein. The superfamily includes the TGF b themselves, the activins and the bone morphogenetic proteins [ BMPs ] . The BMPs constitute the largest family. Each member of the TGF b superfamily binds to a characteristic combination of type I and type II receptors , both of which are required for signaling . Typically , the ligand first binds to and activates a type - II receptor homodimer, which recruits , phoshorylates , and activates a type I receptor homodimer , forming an active tetrameric receptor complex. Once activated , the receptor complex uses a strategy for rapidly relaying the signal to the nucleus that is very similar to the JAK - STAT strategy. The type I receptor directly binds and phosphorlyates a latent gene regulatory protein of the smad family. Activation of Smads causes their translocation from cytoplasm to the nucleus where they function to control gene expression.