Growth Factors – The Cell’s Green Light for Growth
Growth factors are proteins that serve as messengers between cells, helping to regulate key processes such as growth, healing, and cell differentiation. Here's how they work:
- Bind to specific receptors on the surface of target cells to trigger intracellular signaling cascades.
- Their effects vary depending on the type—e.g., EGF, FGFs, and VEGFs stimulate skin, connective tissue, blood vessel, and nerve cell regeneration.
- Once bound, they activate intracellular enzymes that transmit signals to the nucleus.
- These signals lead to the production of proteins that promote the G1-S transition in the cell cycle (the point where a cell commits to division).
Signaling routes include:
- Endocrine, paracrine, autocrine, and intracrine diffusion.
- Direct contact with receptor proteins embedded in membranes or extracellular matrix.
They are vital in stem cell regulation, helping:
- Induce differentiation into specific tissues (e.g., retinal cells for transplantation).
- Reprogram adult cells into induced pluripotent stem cells (iPSCs) using Yamanaka factors (Oct3/4, Sox2, Klf4, and c-Myc).
These factors act as the “GO” signals for the cell cycle, working alongside cyclin-CDK complexes to ensure timely progression through cell division.