Several well-characterized signal transduction pathways are critical in cellular and tissue functions:
1. MAPK/ERK Pathway: This pathway is involved in cell division, differentiation, and survival. It is activated by growth factors binding to RTKs, leading to a cascade that includes the activation of Ras, Raf, MEK, and ERK. 2. PI3K/Akt Pathway: This pathway regulates metabolism, growth, and apoptosis. PI3K activation leads to the production of PIP3, which recruits Akt to the membrane, where it is activated and phosphorylates various downstream targets. 3. JAK/STAT Pathway: Important in immune responses, this pathway is triggered by cytokines binding to receptors, leading to the activation of JAK kinases and subsequent phosphorylation and dimerization of STAT proteins, which then translocate to the nucleus to modulate gene expression.
