Semaphorin-4D (SEMA4D) also known as Cluster of Differentiation 100 (CD100), is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
of the
semaphorin
Semaphorins are a class of secreted and membrane proteins that were originally identified as axonal growth cone guidance molecules. They primarily act as short-range inhibitory signals and signal through multimeric receptor complexes. Semaphorins ...
family that in humans is encoded by the ''SEMA4D''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Function
Semaphorin 4D (Sema 4D) is an
axon guidance molecule which is secreted by
oligodendrocyte
Oligodendrocytes (), or oligodendroglia, are a type of neuroglia whose main functions are to provide support and insulation to axons in the central nervous system of jawed vertebrates, equivalent to the function performed by Schwann cells in the ...
s and induces
growth cone
A growth cone is a large actin-supported extension of a developing or regenerating neurite seeking its synaptic target. It is the growth cone that drives axon growth. Their existence was originally proposed by Spanish histologist Santiago Ram� ...
collapse in the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...
. By binding
plexin B1 receptor it functions as an R-Ras GTPase-activating protein (GAP) and repels axon growth cones in both the mature central nervous system.
In the immune system, CD100 binds
CD72
CD7 (Cluster of Differentiation 7) is a protein that in humans is encoded by the ''CD7'' gene.
Function
This gene encodes a transmembrane protein which is a member of the immunoglobulin superfamily. This protein is found on thymocytes and matur ...
to activate
B cells and
dendritic cells, though much about this interaction is still under investigation.
During
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different de ...
damage repairs, SEMA4D interacts with
Plexin B2 on
Gamma delta T cell
Gamma delta T cells (γδ T cells) are T cells that have a γδ T-cell receptor (TCR) on their surface. Most T cells are αβ (alpha beta) T cells with TCR composed of two glycoprotein chains called α (alpha) and β (beta) TCR chains. In contrast, ...
s to play a role in the healing process.
See also
*
Cluster of differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophen ...
References
Further reading
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
*
Clusters of differentiation
{{membrane-protein-stub