FtsZ functions at an early stage of septum formation. Early in the division cycle, FtsZ is localized throughout the cytoplasm, but prior to cell division.

TLS Online TPP Program

#Id: 1559

#Unit 4. Cell Communication and Cell Signaling

Wnt proteins are synthesized in the ER & modified by the addition of lipids (palmitic and palmitoleic acid).

 

TLS Online TPP Program

#Id: 1560

#Unit 4. Cell Communication and Cell Signaling

Lipid modifications of Wnt are catalyzed by the O-acetyltransferase Porcupine.

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.