The absorption of UV light by nucleic acids arises from n ® p* and p ® p* transitions of the purine and pyrimidine bases that occur between 260nm and 275 nm.

TLS Online TPP Program

#Id: 1565

#Unit 4. Cell Communication and Cell Signaling

Wnt signal transduction pathways classify into:

1. Canonical wnt pathway (β-catenin dependent)

2. Noncanonical wnt pathways (β-catenin independent)

 

TLS Online TPP Program

#Id: 1566

#Unit 4. Cell Communication and Cell Signaling

Noncanonical pathways can be divided into two types: 

1. The “planar cell polarity” pathway

2. The “Wnt/calcium” pathway

TLS Online TPP Program

#Id: 1567

#Unit 4. Cell Communication and Cell Signaling

The central player in the “canonical” Wnt intracellular signal transduction pathway is called β-catenin.

TLS Online TPP Program

#Id: 1568

#Unit 4. Cell Communication and Cell Signaling

Homologs

β-catenin in vertebrates =Armadillo in Drosophila.

TLS Online TPP Program

#Id: 1569

#Unit 4. Cell Communication and Cell Signaling

“canonical” Wnt signaling pathway uses a second transmembrane protein, LRP that associates with Frizzled in a Wnt signal– dependent manner.

 

TLS Online TPP Program

#Id: 1570

#Unit 4. Cell Communication and Cell Signaling

Homologs

LRP in vertebrates = Arrow in Drosophila.