Epigen is an EPGN protein found in humans. It is often referred to by its longer name; epithelial mitogen. As it is encoded by the EPGN gene, this means it is part of the epidermal growth factor family of proteins. In humans, the gene is located on Chromosome 4.
The function of Epigen is similar to that of the other members of the epidermal growth factor family of proteins. Being part of this family will make you a ligand for the epidermal growth factor receptor. One of the major functions of epigen - and other proteins in this family - is cell survival. It works to help repair and fix cells, ensuring they survive longer and don’t die. There are also links between Epigen and cell migration, as well as cell proliferation. Many studies have produced evidence showing Epigen can help with the healing of wounds too.
This particular protein as also been found to contain an extremely high mitogenic activity, with a very low affinity for its receptor. Other functions also include affecting various epidermal structures; including the mammary and sebaceous glands.
Mechanism & Interactions
Epigen is found to interact with various other cells in the body. Primarily, it interacts with the epidermal growth factor receptor, to which it binds. The location of epigen is often found in testis, heart, and liver. However, there are wider expressions found in the pancreas, hair follicles, and even in dorsal root ganglia.
EPGN is shown to infiltrate various epithelial cells of the breast and prostate. It is found that an increased expression in these cells often occurs when cancers are present. When an increased expression of epigen is present - along with TGFA - it becomes easy to predict the growth inhibitory activity of cetuximab. This is an antibody that’s often used to help treat various tumors in the head and neck. If further studies are undertaken, it could prove to be a breakthrough in treating cancer patients with these tumors.
It is thought that the primary influence of this protein is the skin. However, more recent reports show that other organs can also be influenced by epigen as well.
Epigen is the newest epidermal growth factor family member. It is also the 7th ligand of EGFR (epidermal growth factor receptor). It is found on chromosome 4q13.3 in humans, and is often found in the liver. Epigen is a transmembrane glycoprotein that has two sites separated by a cleavage. Here, the two sites will release an EGF-like domain. When soluble, epigen is found to have 152 amino acids. This gives in mitogenic properties beyond that of EGF. However, it has a binding affinity that is much lower - 100 times less to be precise.
The open reading frame of epigen is spread into two exons. The first exon acts as an encoder for the amino-terminal part, while the second encodes the rest of the molecule. It is also found that the open reading frame of epigen is similar to another ligand; epiregulin. As such, they both share the same origin and chromosomal region, and co-align on the same arm of human chromosome 4.