About Glia maturation factor Beta :
Glia maturation factor beta is strongly implicated in the development of the nervous system as well as immune function and angiogenesis. This is another neurotrophic factor crucial for normal development. This was first isolated in 1972 from the Bovine brain. Interestingly, the protein is actually a mixture of two compounds.
Research has shown that GMFB is related to the production of nitric oxide, however, the exact mechanism of how this occurs is not clear. It seems to induce the overexpression of iNOS, which ultimately leads to the increased production of NO. According to studies, iNOS through endotoxin-stimulated glial cells are p38 and ERK-dependent. Research further suggests that p38 MAPK could induce the transcription, potentially by causing the activation of NF-kB. As well as this, there have been reports of cross talk from the ps38 MAPK pathway and the Janus Kinase signal transducer. That said, more research is required to find out more depth about the relationship and mechanism between GMFB, MAPK, NF-kB and JAK-STAT.
The neurotrophic factor is typically expressed in the central nervous system. However, it has also been found in a variety of other tissues. These do include the kidney, thymus and the colon. An incredibly evolutionary conserved protein, it can be expressed in a range of different vertebrates.
Research has explored the function and potential significance for using GMFB to treat neurodegenerative diseases. These include both Alzheimer’s and Parkinson’s due to the loss of neurons that these diseases cause.
Due to not having a signal peptide sequence, it is largely considered that GMFB is an intracellular protein. However, it is implicated in a variety of signalling pathways. It is also possible that GMFB is a secretory protein and has been found to be secreted in certain conditions. Furthermore, GMFB has been found to be expressed on the surface of certain cells. This does include thymus epithelial cell lines and astrocytes. As well as this a vitro study has shown that GMFB can provide signalling as well as metabolic alterations through glioblastoma cells.
The expression of GMFB seems to be development dependent. Studies on rats found that the mRNA was discoverable as early in development as embryonic day 10. The actual protein can be detected in day 14 while expression levels reached peak production one week after birth. Studies have also found that the concentration of the protein remains largely the same through the life of both rats and humans while secretion mechanisms are still unknown.
The Human GMFB can be found on the long arm form human chromosome 14. It has seven exons and six introns while being 7 kb in length. The gene does and an acidic protein at the isoelectric point pH 4.9. Furthermore, when purified, the GMFB protein has been found to have 142 amino acid residues as well as a weight of 17 kDa.
Explorations into the structure of this factor have highlighted differences and similarities with ADF-H. The studies have suggested new ways of exploring the function of this family of proteins.