Retinoic acid-inducible gene-I-like receptors (RLRs) are soluble PRRs that reside in the cytosol of many cell types.

TLS Online TPP Program

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#Unit 4. Cell Communication and Cell Signaling

Upon secretion, Wnt proteins associate with glypicans (heparan sulfate proteoglycan) in the ECM, which restricts diffusion and leads to a greater accumulation of Wnt closer to the source of production.

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#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)

 

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#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

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#Id: 1567

#Unit 4. Cell Communication and Cell Signaling

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

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#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.