Question

What is the importance of relay signaling in development?

Answer 1

Relay signalling is the mechanism by which a signal is passsed along from one part to other part of the cell or body etc. The chains of molecules that relay signals inside a cell are known as intracellular signal transduction pathways like wnt, hedgehog signalling , tyrosine kinase/MPEK etc.

This Cell to cell interactions through signal-transduction pathways are crucial for the coordination of embryonic development and differentiation. These signalling pathways are activated by the binding of a ligand to a transmembrane receptor, which in turn leads to the modification of cytoplasmic transducers and brings about the required response. In the absence of these responses cell fails to grow and differentiate and the development is halted.

There are several examples and studies which have proven the importance and necessity of these signals . one of them are illustrated below :- let's exemplify the notch signalling pathways which plays vere important role  at all stages of development to regulate cell proliferation, survival, and differentiation in organisms ranging from Drosophila and C. elegans to humans. It is a large protein having a single transmembrane domain that serves as a receptor for signaling by transmembrane proteins. The binding of ligands leads to proteolytic cleavage of Notch, and then translocation of intracellular domain of Notch into the nucleus. This intracellular domain then interacts with another transcription factor (ex- Su(H) in Drosophila or CBF-1 in mammals) and induces expression of its target genes. This gene encodes other transcriptional regulatory proteins, which determines the cell fate.