Numerous adult organs possess adult stem cells, which in most cases are multipotent.

TLS Online TPP Program

#Id: 9977

#Unit 4. Cell Communication and Cell Signaling

Unphosphorylated β-catenin translocates to the nucleus.

TLS Online TPP Program

#Id: 9978

#Unit 4. Cell Communication and Cell Signaling

β-catenin binds to TCF to displace the Gro repressor and recruits co-activator proteins Pygo, LGS, to activate target gene expression.

TLS Online TPP Program

#Id: 9979

#Unit 4. Cell Communication and Cell Signaling

Active Wnt signaling leads to the secretion of Notum.

TLS Online TPP Program

#Id: 9980

#Unit 4. Cell Communication and Cell Signaling

Notum, a hydrolase that associates with glypican and then cleaves off Wnt’s attached lipids in a process of deacylation or delipidation.

TLS Online TPP Program

#Id: 9981

#Unit 4. Cell Communication and Cell Signaling

Delipidation process reduces Wnt signaling, creates a negative feedback mechanism for preventing excessive Wnt signaling.

TLS Online TPP Program

#Id: 9982

#Unit 4. Cell Communication and Cell Signaling

Frizzled receptor possesses a unique hydrophobic cleft adapted to interact with lipidated Wnts, a binding conformation mimicked in Notum’s structure as well.