Neuropilin

Neuropilin is a protein receptor active in neurons.

There are two forms of Neuropilins, NRP-1 and NRP-2. They are transmembrane glycoproteins, and predominantly co-receptors for another class of proteins known as semaphorins. Of the semaphorins, NRP-1 and NRP-2 are specifically receptors for class-3 semaphorins, which, among many things, are responsible for axon guidance during the development of the nervous system in vertebrates.

Neuropilins work as co-receptors as they have a very small cytoplasmic domain and thus rely upon other molecules (normally plexins) to transduce their signals across a cell membrane. Neuropilins generally work as dimers and different combinations have different affinities for molecules. For example, NRP-1 homodimers have high affinity for Sema-3A, whilst NRP-2 homodimers have high affinity for Sema-3F.

Another ligand for neuropilins is VEGF, a growth factor involved in the regulation of angiogenesis.

Applications

Neuropilin-1 is a therapeutic target protein in the treatment for leukemia and lymphoma, since It has been shown that there is increased expression in neuropilin-1 in leukemia and lymphoma cell lines. Also, antagonism of neuropilin-1 has been found to inhibit tumour cell migration and adhesion.