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Preferred term

Semaphorins  

Type

  • mesh:Descriptor

Definition

  • A family of proteins that mediate AXONAL GUIDANCE. Semaphorins act as repulsive cues for neuronal GROWTH CONES and bind to receptors on their filopodia. At least 20 different molecules have been described and divided into eight classes based on domain organization and species of origin. Classes 1 and 2 are invertebrate, classes 3-7 are vertebrate, and class V are viral. Semaphorins may be secreted (classes 2, 3, and V), transmembrane (classes 1, 4, 5, and 6), or membrane-anchored (class 7). All semaphorins possess a common 500-amino acid extracellular domain which is critical for receptor binding and specificity, and is also found in plexins and scatter factor receptors. Their C termini are class-specific and may contain additional sequence motifs. Transmembrane proteins involved in axonal guidance of peripheral neurons in the developing CNS of invertebrates. Semaphorin-1 refers to the class of SEMAPHORINS with an extracellular sema domain and a short cytoplasmic domain. Sema-1 was first identified in grasshopper as fasciclin IV, and has since been described in Drosophila and C. elegans. Two distinct members of this class of semaphorins exist: SEMA-1a (the original sema-1) and SEMA-1b, a homologous protein isolated from Drosophila which may be more important for neuronal differentiation than migration.

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Entry terms

  • Semaphorin

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URI

http://data.loterre.fr/ark:/67375/JVR-R23PN1G5-4

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RDF/XML TURTLE JSON-LD Created 7/3/02, last modified 2/26/16