Question

In what type of cell response will you find the RTK-ras-MAP kinase cascade?

Answer 1

Ans. - RTK-receptor tyrosine kinase- MAP means Mitogen-activated pAthway and Ras is an oncogene but also required for signaling since it is a monomeric G protein. These define the componenets of this pathway.

Any ligand such as a growth hormone can bind to a receptor which is the RTK- and then the tyrosine present on these receptors will undergo phosphorylation. This will then activate the G protein which will be initially in an inactive form- this G protein here is RAS.

This results in a series of signalling reactions having phosphorylation activity and hence ultimately. The activated signal enters the nucleus for gene transcription and there is the required signal or the activity to be found.

This signalling is for growth and proliferation of cells , cell death and morphogenesis as well, so all eukaryotic cells are capable for this pathway.

yeasts and cells of higher eukaryotes contain multiple MAP kinases.

Activation of MAP kinase in two different, remarkable convergence of biochemical and genetic studies in yeast, C. elegans, Drosophila, and mammals has revealed a highly conserved cascade of protein kinases that operate in sequential fashion downstream from activated RAS.

If you have any doubt then mention in comment.