IBSP

The protein encoded by this gene is a major structural protein of the bone matrix. It constitutes approximately 12% of the noncollagenous proteins in human bone and is synthesized by skeletal-associated cell types, including hypertrophic chondrocytes, osteoblasts, osteocytes, and osteoclasts. The only extraskeletal site of its synthesis is the trophoblast. This protein binds to calcium and hydroxyapatite via its acidic amino acid clusters, and mediates cell attachment through an RGD sequence that recognizes the vitronectin receptor.

Full Name

Integrin Binding Sialoprotein

Function

Binds tightly to hydroxyapatite. Appears to form an integral part of the mineralized matrix. Probably important to cell-matrix interaction. Promotes Arg-Gly-Asp-dependent cell attachment.

Biological Process

Bone mineralization Source: GO_Central
Cell adhesion Source: UniProtKB
Cellular response to growth factor stimulus Source: UniProtKB
Extracellular matrix organization Source: UniProtKB
Osteoblast differentiation Source: UniProtKB
Positive regulation of cell adhesion Source: CAFA

Cellular Location

Secreted

PTM

N-glycosylated; glycans consist of sialylated and core-fucosylated bi-, tri- and tetraantennary chains.
O-glycosylated at eight sites; mucin-type glycans contain Gal, GlcNAc, GalNAc and terminal NeuAc.
Sulfated on either Tyr-313 or Tyr-314.