CSB327H1 Lecture Notes - Lecture 15: Bone Sialoprotein, Type I Collagen, Intramembranous Ossification
28 Dec 2012
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Document Summary
Types of bone: cortical bone (lamellar/compact) is dense, found in the shaft of long bones, spongy bone (trabecular/cancellous) is lighter and less dense, consists of plates (trabeculae) Sibling family of small calcium binding glycoproteins that bind to integrin: bone sialoprotein (bsp) promote mineralization. Binding of ha to stretches of glutamic residues. Rfd integrin binding site (e. g. , bsp is integrin binding protein) Bone specific: osteopontin (opn) block mineralization. Binding of ha to polyaspartic acid motif. Rgd integrin binding site (e. g. , opn is integrin binding protein) Broad tissue distribution: expressed in tissues that undergo mineralization, but also found in other tissues (except bsp) 5% cells (e. g. , osteoblasts, osteocytes, osteoclasts, etc. : 70% hydroxyapatite, 5% water. Temporal expression of bone-associated genes: proliferation differentiation mineralization, bsp is expressed at the onset of mineralization. Bsp interacts with 2 chain of type i collagen. Bsp is localized in hole zone of collagen fibrils. Ha is localized in hole zone too.
