Mitogen

Mitogen is a type of substance that encourages a cell to commence cell division, triggering mitosis. Mitogens function by overcoming the cell's checkpoints, pushing the cell cycle forward even in the absence of further stimulation.

Mitogens are typically derived from a foreign organism (a virus or bacteria), and stimulate cell proliferation by mimicking the activity of normal growth factors. They are often used in the laboratory to stimulate cell proliferation in cell culture.

Mechanism of action

Mitogens work by triggering the G1 phase of the cell cycle, the phase in which the cell prepares for DNA replication. They do this by activating the Ras protein, which in turn activates the MAPK/ERK pathway. This pathway leads to the activation of the cyclin D/CDK4 complex, which pushes the cell past the G1 checkpoint and into the S phase, where DNA replication occurs.

Examples of mitogens

Some examples of mitogens include:

• Epidermal growth factor (EGF)
• Platelet-derived growth factor (PDGF)
• Insulin-like growth factor (IGF)
• Vascular endothelial growth factor (VEGF)
• Fibroblast growth factor (FGF)

Role in disease

Mitogens can play a role in the development of cancer. If a cell is stimulated to divide too often, or if the checkpoints that normally control cell division are not functioning properly, the cell can become cancerous. Some viruses, such as the Human papillomavirus (HPV), are known to produce mitogens that stimulate the host cell to divide, leading to the development of cancer.

See also

• Growth factor
• Cell cycle
• Cancer