The amount of BSP in bone and dentin is roughly equal,[16] however the function of BSP in these mineralized tissues is not known. One possibility is that BSP acts as a nucleus for the formation of the first apatite crystals.[17].As the apatite forms along the collagen fibres with in the extracellular matrix, BSP could then help direct, redirect or inhibit the crystal growth.
Tags: Proteins
It has been shown that osteopontin and bone sialoprotein, bone matrix phosphoproteins, are highly efficient in vitro TRAP substrates, which bind to osteoclasts when phosphorylated.[13] Upon partial dephosphorylation, both osteopontin and bone sialoprotein are incapable of binding to osteoclasts. From this effect, it has been hypothesized that TRAP is secreted from the ruffled border, dephosphorylates osteopontin and allows osteoclast migration, and further resorption to occur.
Bone sialoprotein (BSP) is a component of mineralized tissues such as bone, dentin, cementum and calcified cartilage. BSP is a significant component of the bone extracellular matrix and has been suggested to constitute approximately 8% of all non-collagenous proteins found in bone and cementum [1]. BSP was originally isolated from bovine cortical bone as a 23-kDa glycopeptide with high sialic acid content, as described in separate reports by Williams and Peacocke [2] and Andrews and Herring [3] in 1965. Native BSP has an apparent molecular weight of 60-80 kDa based on SDS-PAGE, which is a considerable deviation from the predicted
Secreted phosphoprotein 1 (osteopontin, bone sialoprotein I, early T-lymphocyte activation 1), also known as SPP1 and commonly referred to as osteopontin, is a human gene.[1] Osteopontin is a glycoprotein first identified in 1986 in osteoblasts. The prefix of the word "osteo" indicates that the protein is expressed in bone. The suffix "-pontin" is derived from "pons," the Latin word for bridge, and signifies osteopontin's role as a linking protein. Osteopontin is an extracellular structural protein and therefore an organic component of bone. Synonyms for this protein include sialoprotein I and 44K BPP (bone phosphoprotein). The gene has 7 exons, spans 5
The exact physiological role(s) of TRAP is unknown, but many functions have been attributed to this protein. In knockout mice studies, those with a phenotype of TRAP-/- showed mild osteopetrosis, with greatly reduced osteoclast activity, resulting in thickening and shortening of the cortices, the formation of club-like deformities in the distal femur, and widened epiphyseal growth plates with delayed mineralization of cartilage, all of which increased with age.[11] Likewise in TRAP overexpressing transgenic mice, mild osteoporosis occurred along with increased osteoblast activity and bone synthesis.[12] Proposed functions of TRAP include osteopontin /bone sialoprotein dephosphorylation, the generation of reactive oxygen species
Bone hemostasis is the process of controlling the bleeding from bone. Bone is a living vascular organ containing channels for blood and bone marrow. When a bone is cut during surgery bleeding can be a difficult problem to control, especially in the highly vascular bones of the spine and sternum. Bleeding from soft tissue is normally stopped using a cautery that creates heat, causing blood vessels to collapse and become sealed. Since the blood in living bone flows through channels in the bone that do not collapse, a cautery is not effective in preventing bone bleeding. Blocking the holes
The protein encoded by this gene is a member of the TGF-? superfamily. Like other members of the bone morphogenetic protein family of proteins, it plays a key role in the transformation of mesenchymal cells into bone and cartilage. It is inhibited by noggin and a similar protein, chordin, which are expressed in the Spemann-Mangold Organizer. BMP7 may be involved in bone homeostasis. It is expressed in the brain, kidneys and bladder.[2] BMP7 induces the phosphorylation of SMAD1 and SMAD5, which in turn induce transcription of numerous osteogenic genes.[3] It has been demonstrated that BMP7 treatment is sufficient to induce all
Bone morphogenetic protein 8A (BMP8A) is a polypeptide member of the TGF? superfamily of proteins. It, like other bone morphogenetic proteins (BMPs) is involved in the development of bone and cartilage. BMP8A may be involved in epithelial osteogenesis. It also plays a role in bone homeostasis. It is a disulfide-linked homodimer.
Ipriflavone is a synthetic isoflavone which is used to inhibit resportion,[1] maintain bone density and to prevent osteoporosis in postmenopausal women. It is not used to treat osteoporosis. It slows down the action of the osteoclasts (bone-eroding cells), allowing the osteoblasts (bone-building cells) to build up bone mass.
BMP-2 like other bone morphogenetic proteins,[2] plays an important role in the development of bone and cartilage. It is involved in the hedgehog pathway, TGF beta signaling pathway, and in cytokine-cytokine receptor interaction. It is involved also in cardiac cell differentiation and epithelial to mesenchymal transition. BMP-2 and BMP-7 are osteogenic BMPs: they have been demonstrated to potently induce osteoblast differentiation in a variety of cell types.[3]
Bone Morphogenetic Proteins (BMPs) are a group of growth factors and cytokines known for their ability to induce the formation of bone and cartilage.
As osteocalcin is manufactured by osteoblasts, it is often used as a biochemical marker, or biomarker, for the bone formation process. It has been routinely observed that higher serum-osteocalcin levels are relatively well correlated with increases in bone mineral density (BMD) during treatment with anabolic bone formation drugs for osteoporosis, such as Forteo. In many studies, Osteocalcin is used as a preliminary biomarker on the effectiveness of a given drug on bone formation.
Bone morphogenetic protein 2 is shown to stimulate the production of bone and recombinant human protein (rhBMP-2) and is currently available for orthopaedic usage in the United States.[4] Implantation of BMP-2 in a collagen sponge induces new bone formation and can be used for the treatment of bony defects, delayed union, and non-union.[5] Bone morphogenetic protein 2 has also found its way into the field of Dentistry. Oral Surgery and Implant Dentistry in particular have benefited dramatically from commercially available BMP-2.
Osteopontin has been implicated as an important factor in bone remodeling.[2] Specifically, research suggests it plays a role in anchoring osteoclasts to the mineral matrix of bones.[3] The organic part of bone is about 20% of the dry weight, and counts in, other than osteopontin, collagen type I, osteocalcin, osteonectin, bone sialo protein and alkaline phosphatase. Collagen type I counts for 90% of the protein mass. The inorganic part of bone is the mineral hydroxyapatite, Ca10(PO4)6(OH)2. Loss of this mineral may leads to osteoporosis, as the bone is depleted for calcium if this is not supplied in the diet.
Bone marrow stromal cell antigen 2, also known as BST2, is a human gene.[1] BST2 has also been designated as CD317 (cluster of differentiation 317). Bone marrow stromal cells are involved in the growth and development of B-cells. The specific function of the protein encoded by the bone marrow stromal cell antigen 2 is undetermined; however, this protein may play a role in pre-B-cell growth and in rheumatoid arthritis.[1
Bone morphogenetic protein 3 (osteogenic), also known as BMP3 or osteogenin, is a human gene.[1] The protein encoded by this gene is a member of the transforming growth factor beta superfamily. It, like other bone morphogenetic proteins (BMP's) is known for its ability to induce bone and cartilage development. It is a disulfide-linked homodimer. It negatively regulates bone density. BMP3 is an antagonist to other BMP's in the differentiation of osteogenic progenitors. It is highly expressed in fractured tissues.