PDGF
Meaning of PDGF: A signal released when a vessel is torn, telling repair cells to multiply and move toward the damage.
Definition of PDGF
PDGF stands for platelet-derived growth factor, a family of signaling proteins that tell certain cells to divide, move and rebuild tissue. Platelets release it at the site of an injury, and it is also made by smooth muscle cells, immune cells and many tumors. Its main targets are connective tissue cells, the cells that wrap blood vessels, and the cells that lay down scar.
What does it do in a wound?
When a vessel tears, platelets stick to the exposed edge and empty their granules. PDGF is one of the proteins released. It draws in fibroblasts and immune cells, and it tells them to divide. Fibroblasts then produce collagen, the fibrous protein that gives a healing wound its strength. PDGF also recruits pericytes, the cells that wrap around a new capillary and make it stable, so it supports both the framework and the plumbing of repaired tissue.
How does the signal reach the inside of a cell?
| Step | What happens |
|---|---|
| Release | Platelets and other cells secrete PDGF |
| Binding | It attaches to a receptor on the target cell surface |
| Activation | Two receptors pair up and switch on their inner enzyme |
| Response | The cell divides, migrates or makes matrix |
The receptor is a tyrosine kinase, meaning the part inside the cell adds phosphate groups to other proteins and starts a relay of signals. Nothing crosses the membrane; the message is handed on.
Why does it matter in disease?
A growth signal that is switched on permanently drives growth that is not needed. Several tumors carry faults in the PDGF system, either making too much of the growth factor or carrying a receptor stuck in the on position. Certain sarcomas and gastrointestinal stromal tumors are examples, and drugs that block these receptors are used against them. The same signaling contributes to scarring in the lung, liver and kidney, and to the thickening of a blood vessel wall after injury, where smooth muscle cells multiply and narrow the channel.
Also known as
Used in a sentence
The tumor showed a mutation in the PDGF receptor gene.
Good to know
PDGF is a normal repair signal, and its role in disease comes from persistent activation rather than from the molecule itself, which is why receptor blockers are used in some tumors.