Glycoproteins

Proteins with attached carbohydrates

TLS Online TPP Program

#Id: 1561

#Unit 4. Cell Communication and Cell Signaling

Principal signaling receptor for Wnt proteins is Frizzled (Fz), which contains seven transmembrane α helices.

TLS Online TPP Program

#Id: 1562

#Unit 4. Cell Communication and Cell Signaling

Lipidated Wnt can bind to Frizzled receptor because lipids are essential for Wnt to bind to Frizzled.

TLS Online TPP Program

#Id: 1563

#Unit 4. Cell Communication and Cell Signaling

This is the example of post-translational modification by a lipid that mediates a ligand-receptor interaction.

TLS Online TPP Program

#Id: 1564

#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.

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