Cellular responses are triggered by proteins, drugs, or pathogens binding to specific receptors. Receptor mediated signaling is a cascade of enzymatic reactions that amplifies the signal. The agonists and antagonists modulating receptor functionality are essential tools for research and medical practice.
The receptors are divided into 2 categories:
Cell surface receptors
G-protein coupled receptor
Tyrosine kinase receptor
Ligand-gated ion channel
Toll gate receptor
Intracellular nuclear and cytoplasmic receptors
Steroid hormone receptors enter the nucleus and directly bind to DNA to regulate gene expression.
The major signaling pathways in mammals include:
Growth factor pathway
Toll-like receptor pathway
Wnt signaling pathway
These pathways intersect and cross-talk, increasing signal diversity.