The age structure of a population is the proportion of individuals that occurs in different age classes.

TLS Online TPP Program

#Id: 9970

#Unit 4. Cell Communication and Cell Signaling

In the absence of Wnts,

“free” β-catenin are targeted for degradation by a cytosolic destruction complex that is held together by the tumor suppressor protein Axin.

TLS Online TPP Program

#Id: 9971

#Unit 4. Cell Communication and Cell Signaling

β-catenin Destruction Complex contains:

Tumor suppressor APC

Dvl protein

Constitutively active protein kinases GSK 3β and CK1

TLS Online TPP Program

#Id: 9972

#Unit 4. Cell Communication and Cell Signaling

Kinases CK1 and GSK3,

sequentially phosphorylate β-catenin at multiple serine and threonine residues

TLS Online TPP Program

#Id: 9973

#Unit 4. Cell Communication and Cell Signaling

E3 βTrCP ubiquitin ligase then binds to two phosphorylated residues on β catenin, leading to ubiquitinylation and degradation in proteasomes.

TLS Online TPP Program

#Id: 9974

#Unit 4. Cell Communication and Cell Signaling

In the absence of Wnt,

TCF is associated with transcriptional repressor proteins Groucho (Gro) that inhibit gene transcription in nucleus

TLS Online TPP Program

#Id: 9975

#Unit 4. Cell Communication and Cell Signaling