About SPARC / Secreted Protein Acidic & Rich in Cysteine:
SPARC stands for Secreted Protein Acidic and Rich in Cysteine. It is an extracellular Ca (2+) binding matricellular glycoprotein that has been observed by researchers to associate with cell populations that are undergoing migration, differentiation, and morphogenesis.
It functions to encode a cysteine-trich acidic matrix-associate protein. The job of the encoded protein is to ensure that the collagen in bone can become calcified, though it also has other functions -- for example, it has also been shown to play a role in extracellular matrix synthesis and helps to promote changes to the shape of the cell. Under observation, there have been suggestions that the gene may help with tumor suppression. However, it has also been linked to the opposite -- because it promotes change to cell shape, it is linked with metastasis, which can then result in the invasion of tumor cells. So far for this gene, there have been three different transcript variants that encode different isoforms.
In endothelial cells, the SPARC functions in vitro are counter adhesion and antiproliferation. However, which mechanisms are engaged to promote these antitumor effects have not yet been made clear through research. There have been a host of diseases that have become associated with the protein coding gene SPARC. For instance, Brittle Bone Disorder, Osteogenesis Imperfecta, and Type Xvii. In terms of related pathways, you’ll find that there’s a response to elevated platelet cytosolic Ca2+, as well as binding and uptake of ligands by scavenger receptors. One of the most important paralogs of this gene is SPARCl1.