About AGR / Anterior Gradient Protein:
Anterior gradient protein 2 homolog (AGR-2), is a protein found in the human body and in encoded by the AGR2 gene. This protein can also be known as secreted cement gland protein XAG-2 homolog. Anterior gradient homolog 2 was first discovered in Xenopus laevis which is known as the African clawed frog. Inside this animal, AGR plays an important role in cement gland differentiation.
Anterior Gradient Protein Function
In humans, cancer cells with a high level of AGR2 correlates with downregulation or the p53 response. The P53 response mediates the cellular response to DNA damage and triggers DNA repair and this is something that is crucial for the body. It also correlated with the downregulation of cell migration and cell transformation. It has also been observed in several cases that the AGR2 protein can repress cell growth as well as proliferation. This is something that could in theory reduce the risk of certain cancers.
AGR2 is a protein disulfide isomerase and contains a single CXXS domain within the protein for both oxidation and reduction reactions. AGR2 forms intestinal mucin as well as other mixed disulphides in substrates. The interaction of AGR2 with Mucin 2 forms a heterodisulfide bond in MUC2.
Anterior Gradient Protein Interactions
It is important to note that AGR2 plays an important role in protein folding, and it contains a KTEL C-terminal motif that is similar to both KDEL and KVEL endoplasmic reticulum retention sequences.
AGR2 protein interacts with C4.4A and DAG-1 proteins. These proteins are associated with metastasis which is the spread of cancer cells from their origin in the body to other parts of the body. AGR2 has also been known to bind to reptin which is a tumour repressor.