Hedgehog Signaling Pathway in Vertebrates | Purpose and Mechanism

The video tutorial explains the Hedgehog signaling pathway in vertebrates, comparing it to invertebrates. It covers the pathway's roles in development, patterning, and tissue repair, and introduces concepts like graded signaling and organ-specific gene induction. Differences between vertebrate and invertebrate signaling are highlighted, focusing on the primary cilium and Glee proteins. The video details the inactivation and activation mechanisms of the pathway, emphasizing the roles of proteins like Smoothened and Sonic Hedgehog. The tutorial concludes with a summary of key points.

What roles does the Hedgehog signaling pathway play in vertebrates?

• It is involved in embryological development only.

• It controls development, patterning, tissue growth, and homeostasis.

• It is responsible for digestion and metabolism.

• It only functions in the cerebellum.

What is the concept of graded signaling in the Hedgehog pathway?

• It means different gradients of hedgehog protein induce different subsets of genes.

• It refers to the uniform activation of all genes.

• It is unrelated to gene activation.

• It involves the activation of genes only in the brain.

Where does Hedgehog signaling occur in invertebrates?

• In the primary cilium of the cell.

• In the cytoplasm.

• In the mitochondria.

• In the nucleus.

What happens to Glee proteins when the Hedgehog pathway is inactivated?

• They are phosphorylated and remain in their full form.

• They are cleaved into truncated repressor forms.

• They are transported out of the cell.

• They bind to DNA and activate gene expression.

Which proteins facilitate the binding of Sonic Hedgehog to patched?

• CDO, BOC, Gas1, and LRP2

• Kif3A and beta-arrestin

• Glee2 and Glee3

• CKI and GPRK2

What occurs when Smoothened is no longer inhibited?

• It binds to DNA directly.

• It is degraded by the proteasome.

• It enters the plasma membrane of the primary cilium.

• It remains in the cytosol.

What is the result of Glee proteins remaining in their full form?

• They exit the cell.

• They are degraded by the proteasome.

• They activate Glee target genes.

• They inhibit transcriptional activation.