Page 27 - Cell biology PDG 2024
P. 27
CHAPTER 3
CELL RECEPTORS, SIGNALING AND COMMUNICATION
Cell receptors
Cellular receptors are proteins either inside a cell or on its
surface
A) Cell surface receptors:
Also known as transmembrane receptors.
They are proteins present on the surface of cells and span the plasma
Ligands that cannot path through the cell membrane membrane.
binds to them. These ligands are often hydrophilic ligands or ones too
large to make it through. The transmembrane receptors don’t bind
DNA to modify gene transcription and translation themselves but
they perform signal transduction instead; an extracellular signal
triggers an intracellular signal, which will usually go to the nucleus to
make a cell do a certain specific function
Structure of cell surface receptors:
The cell surface receptor is formed of an external ligand-binding
domain, a hydrophobic region that spans the membrane, and an
intracellular domain that is responsible for starting a second
messenger cascade.
Examples of Cell surface receptors:
Ion channel receptors, GPCRs, Enzyme linked receptors
۲٦
