In the thick segment of the ascending loop of Henle, paracellular reabsorption of cations, such as Mg++, Ca++, Na+, and K+ occur

TLS Online TPP Program

#Id: 1556

#Unit 4. Cell Communication and Cell Signaling

The defining property of Wnt proteins is 22 cysteine residues, which form disulfide bridges that maintain a globular secondary structure.

 

TLS Online TPP Program

#Id: 1557

#Unit 4. Cell Communication and Cell Signaling

Wnt = wingless + integrated

TLS Online TPP Program

#Id: 1558

#Unit 4. Cell Communication and Cell Signaling

Wnt proteins are essential for- 

Brain development

Limb patterning

Organogenesis

Formation of osteoblasts

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.