Semaphorins

Semaphorins are a class of proteins that are involved in various processes that regulate cellular development. They are named for their role in guiding the path of axon growth cones, which are structures at the tip of a developing axon that play a crucial role in the development of the nervous system. Semaphorins are also involved in other processes such as immune response, angiogenesis, and tumor growth.

History

Semaphorins were first identified in the 1990s as axon guidance molecules. Since then, they have been found to play roles in many other biological processes. The name "semaphorin" comes from the Greek word "semaphore," which means "sign bearer."

Structure

Semaphorins are characterized by a conserved amino acid sequence known as the sema domain. This domain is approximately 500 amino acids in length and is found in all semaphorins. The sema domain is responsible for the binding of semaphorins to their receptors.

Function

Semaphorins function by binding to specific receptors on the surface of cells. These receptors are typically members of the plexin and neuropilin families. Upon binding to their receptors, semaphorins trigger intracellular signaling pathways that regulate cellular behavior.

Role in disease

Semaphorins have been implicated in a variety of diseases, including cancer, neurodegenerative diseases, and cardiovascular diseases. In cancer, semaphorins can either promote or inhibit tumor growth, depending on the context. In neurodegenerative diseases, semaphorins have been found to contribute to the death of neurons.

See also

• Axon guidance
• Plexin
• Neuropilin

References

Semaphorins Resources
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