Question

Mutations of which components in the FGF8-RTK signaling pathway might result in genetic heterogeneity? Why?

Answer 1

Fibroblast growth factor 8 is a protein in humans which is encoded by FGF8 gene. Receptor Tyrosine Kinases (RTKs) are membrane-bound kinases. These RTKs are activated upon binding of receptor-specific ligands.

In the process of optic vesicle induction of surface ectoderm to become lens, optic vesicle secretes FGF8. Then overlying ectoderm makes receptors (RTKs) for FGF8.

Binding of FGF8 to tyrosine kinase receptor induces the signaling pathway, which inturn activates the transcription factors, which results in the expression of proteins of FGF 8 in order to make the lens.

The Tyrosine Kinase is causing the activation of Transcription Factors.

Many cancer cells have mutations affecting RTKs on their targets. atleast 7 mutations take place in FGF8 gene, which results in a special syndrom called, Kallman syndrome. These mutations reduce or eliminate the protein's function. Shortage of functional FGF8 disrupts the migration and survival of olfactory neurons.