GPC3 : glypican 3
Description
The GPC3 (glypican 3) is a protein-coding gene located on chromosome X.
The GPC3 gene provides instructions for making a protein called glypican 3. This protein is one of several glypicans in humans, each of which consists of a core protein attached to long sugar molecules called heparan sulfate chains. Glypicans are anchored to the outer cell membrane, where they interact with a variety of other proteins outside the cell. Glypicans appear to play important roles in development before birth. These proteins are involved in numerous cell functions, including regulating cell growth and division (cell proliferation) and cell survival. Several studies have found that glypican 3 interacts with other proteins at the surface of cells to restrain cell proliferation. Specifically, glypican 3 blocks (inhibits) a developmental pathway called the hedgehog signaling pathway. This pathway is critical for cell proliferation, cell specialization, and the normal shaping (patterning) of many parts of the body during embryonic development. Researchers believe that in some cell types, glypican 3 may act as a tumor suppressor, which is a protein that prevents cells from growing and dividing in an uncontrolled way to form a cancerous tumor. Glypican 3 may also cause some types of cells to self-destruct (undergo apoptosis) when they are no longer needed, which can help keep growth in check. Although glypican 3 is known primarily as an inhibitor of cell growth and cell division, in some tissues it appears to have the opposite effect. Research suggests that in certain types of cells, such as cells in the liver, glypican 3 may interact with proteins called growth factors to promote cell growth and cell division.
Glypican-3 is a cell surface proteoglycan that plays a role in regulating various cellular processes. It negatively regulates the hedgehog signaling pathway by competing with the hedgehog receptor PTC1 for binding to hedgehog proteins, leading to internalization and degradation of the complex. Glypican-3 also positively regulates both the canonical and non-canonical Wnt signaling pathways by interacting with Wnt receptors and ligands. It binds to CD81, reducing its availability for binding to the transcriptional repressor HHEX, resulting in nuclear translocation of HHEX and transcriptional repression. Glypican-3 inhibits the dipeptidyl peptidase activity of DPP4 and plays a role in limb patterning and skeletal development by controlling the cellular response to BMP4. It modulates the effects of growth factors BMP2, BMP7 and FGF7 on renal branching morphogenesis and is required for coronary vascular development. Glypican-3 also plays a role in regulating cell movements during gastrulation.
GPC3 is also known as DGSX, GTR2-2, MXR7, OCI-5, SDYS, SGB, SGBS, SGBS1.
