Lecture Notes
Topic: Cellular Signalling and Regulation
Cellular signalling relies on the precise interaction between ligands and receptors, allowing
cells to respond appropriately to internal and external stimuli.
Signal amplification is a key feature of many pathways, where a single ligand binding event
can trigger a large intracellular response.
Second messengers such as cyclic AMP and calcium ions play a central role in propagating
signals within the cytoplasm.
The specificity of a signalling pathway is determined not only by receptor type, but also by the
downstream proteins expressed in the cell.
● Receptor binding induces a conformational change
● Activation of intracellular signalling cascades
● Signal termination via feedback mechanisms
● Tight regulation prevents aberrant cellular responses
Key Takeaway:
Cells integrate multiple signalling inputs to maintain homeostasis and coordinate complex
physiological processes.