During cleavage, β-catenin enters the nuclei and binds with Tcf3 to form a transcription factor that activates genes encoding proteins Siamois and Twin.

TLS Online TPP Program

#Id: 10539

#Unit 4. Cell Communication and Cell Signaling

Trophic factors (NGF) leads to activation of receptor tyrosine kinases (TrkA) and activation of the protein kinase B pathway

TLS Online TPP Program

#Id: 10540

#Unit 4. Cell Communication and Cell Signaling

PKB phosphorylates Bad, and phosphorylated Bad forms a complex with a cytosolic 14-3-3 protein.

TLS Online TPP Program

#Id: 10541

#Unit 4. Cell Communication and Cell Signaling

In the absence of trophic factors, nonphosphorylated

Bad binds to Bcl-2, releasing Bax and Bak and allowing them to form oligomeric membrane pores and holes.

TLS Online TPP Program

#Id: 10542

#Unit 4. Cell Communication and Cell Signaling

DNA damage or UV irradiation leads to induction of synthesis of the BH3-only Puma protein which binds to Bak and Bax as well as to Bcl-2, allowing Bak and

Bax to form oligomeric pores.

TLS Online TPP Program

#Id: 10543

#Unit 4. Cell Communication and Cell Signaling

Removal of a cell from its substratum disrupts integrin signaling, leading to release of the BH3-only Bim

protein from the cytoskeleton which binds to Bak and Bax to promote pore formation.

TLS Online TPP Program

#Id: 10544

#Unit 4. Cell Communication and Cell Signaling

Two BH3-only proteins, Puma and Noxa are transcriptionally induced by the p53 protein