Semaphorins

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Semaphorins (Greek semaphore for signal) are a class of secreted or membrane-associated proteins that are involved in axonal pathfinding in the central nervous system through repulsive or attractive interaction with neuropilin and plexin receptors.

function

A targeted control of the muscles is essential for every animal. In order to make this possible, muscle fibers and motor neurons must grow and be networked with one another precisely during formation ( ontogenesis ) . The release of semaphorin as a guiding molecule and the sensor technology of the semaphorin receptors on the nerve fibers enable coordination. This z. B. enables a pulse to be sent to the spinal cord or CNS via its associated sensory nerve connection after local stimulation of pressure sensors of a certain skin area and this, as a reaction via location-specific motor neurons, triggers the activation of very specific muscles for coordinated movement with high precision.

In addition to inducing the sprouting and growth of nerve cells (see nerve growth factor ), it is also important to limit the growth so as not to overshoot the target. This growth limitation is also taken over by the semaphorins (together with probably other molecules).

Subdivision

Semaphorins are divided into eight classes: 1 through 7 and V. Classes 1 and 2 occur only in insects and worms , 3 through 7 in vertebrates , and V in viruses . Human semaphorin genes are:

Individual evidence

  1. ↑ Rosa-Eva Hüttl, Andrea Huber Brösamle: Through communication to the goal - nerve fiber interactions during embryonic development. In: DZKF , Volume 16 (1/2), 2012, pp. 20–23.