Auxin-induced proton extrusion acidifies the cell wall and increases cell extension

Auxin increase the rate of proton extrusion (wall acidification), and the kinetics of proton extrusion should closely match those of auxin-induced growth.

TLS Online TPP Program

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#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

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#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

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#Unit 4. Cell Communication and Cell Signaling

Homologs

β-catenin in vertebrates =Armadillo in Drosophila.

TLS Online TPP Program

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#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

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#Unit 4. Cell Communication and Cell Signaling

Homologs

LRP in vertebrates = Arrow in Drosophila.

TLS Online TPP Program

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#Unit 4. Cell Communication and Cell Signaling

In the absence of Wnts,

β-catenin is bound in a complex with Axin (a scaffold protein), APC, and kinases CK1 and GSK3.