MAPK signalling
Step-by-step explanation:
MAPK stands for mitogen activated protein kinase
- Ras-MAPK pathway includes cell division and differentiation
- All growth factors which induce cell division transfer their signal by Ras-MAPK pathway
- Ras-MAPK pathway starts with the binding of insulin hormone to receptor and autophosphorylation on its own tyrosine residue
- Phosphotyrosine residue of receptor recognized by a scaffold protein called insulin receptor substrate(IRS-1)
- Phosphotyrosine residue of IRS-1 recognized by a signaling protein called Grb2
- Grb2 binds to the phosphotyrosine of IRS-1 and provides binding site for SOS protein
- SOS binds to Grb2,then to Ras and act as guanosine exchange factor causing exchange of GDP to GTP on Ras protein
- Ras is a monomeric protein and activated Ras binds to kinase protein and activate it through phosphorylation which further leads to initiation of cell division
- If cells are injected with a non-hydrolyzable form of GTP then Ras would be active all the time which will lead to uncontrolled cell division(cancer)