IBSP (Integrin-Binding Sialoprotein), also known as bone sialoprotein II, is a secreted glycoprotein predominantly expressed in mineralized tissues, including bone, dentin, and cementum. It belongs to the SIBLING (Small Integrin-Binding Ligand N-linked Glycoprotein) family and plays a critical role in bone metabolism, particularly in osteoblast-mediated matrix mineralization and osteoclast regulation. Structurally, IBSP contains an Arg-Gly-Asp (RGD) motif that enables binding to integrin receptors (e.g., αvβ3) on cell surfaces, facilitating cell-matrix interactions. It also interacts with hydroxyapatite crystals, promoting biomineralization.
IBSP antibodies are essential tools in studying skeletal development, bone remodeling, and pathologies like osteoporosis or cancer bone metastasis. In oncology, IBSP is overexpressed in bone-homing cancers (e.g., breast, prostate), making its antibodies valuable for detecting metastatic potential. Researchers use IBSP antibodies in techniques like Western blot, immunohistochemistry (IHC), and immunofluorescence (IF) to localize and quantify IBSP expression in tissues or cell cultures.
Commercial IBSP antibodies are typically raised in rabbits or mice using recombinant protein fragments or synthetic peptides. Specificity validation via knockout controls or siRNA knockdown is crucial due to potential cross-reactivity with other SIBLING proteins. Recent studies also explore IBSP's role in tissue engineering and regenerative medicine, emphasizing its dual function in mineralization and cell signaling.