Biosignaling - Canonical Wnt β-catenin Signaling

The video tutorial explains the canonical Wnt signaling pathway, focusing on the role of Wnt as a chemical signal that binds to receptors like Frizzled and LPR 6. It details the formation and function of the beta-catenin destruction complex, which regulates gene expression by phosphorylating beta-catenin, leading to its degradation. When Wnt binds to its receptors, this complex is inactivated, allowing beta-catenin to enter the nucleus and activate target genes. The tutorial emphasizes the pathway's importance in developmental biology and cellular changes.

What is the primary role of Wnt in the canonical signaling pathway?

• To inhibit cell division

• To degrade proteins

• To act as a chemical signal

• To bind to DNA directly

What is the name of the Wnt receptor located in the plasma membrane?

• LPR6

• Frizzled

• DVL

• APC

Which complex is responsible for the degradation of beta-catenin in the absence of Wnt?

• Frizzled complex

• TCF complex

• LPR6 complex

• Beta-catenin destruction complex

What happens to beta-catenin when it is phosphorylated by GSK3 and CK1?

• It binds to TCF

• It is degraded by the proteasome

• It enters the nucleus

• It activates Wnt target genes

How does Wnt binding affect the beta-catenin destruction complex?

• It inactivates and immobilizes the complex

• It promotes beta-catenin degradation

• It activates the complex

• It enhances beta-catenin phosphorylation

What is the role of TCF in the Wnt signaling pathway?

• To bind with beta-catenin and activate gene transcription

• To phosphorylate proteins

• To inhibit Wnt binding

• To degrade beta-catenin

What determines whether Wnt target genes are turned on or off?

• The amount of TCF present

• The number of Frizzled receptors

• The phosphorylation state of beta-catenin

• The presence of LPR6