Isolation of a novel insulin-like growth factor (IGF) binding protein from human bone: a potential candidate for fixing IGF-II in human bone.
Insulin-like growth factor-II (IGF-II) is the most abundant growth factor stored in human bone. Upon release from this storage depot, IGF-II could act in bone repair and in the coupling of bone formation to bone resorption, a process inherent to bone which is a key regulatory process for maintenance of bone tissue. In this study, we report the isolation and characterization of a novel IGF binding protein (IGFBP) from human bone and describe how this IGFBP may be involved in the fixation of IGF-II in human bone. This new IGFBP has an apparent molecular weight of 29 kDa and has several fold higher affinity for IGF-II than IGF-I which could explain the much greater abundance of IGF-II than IGF-I in human bone. In terms of biological activity, this IGFBP was found to potentiate the proliferative actions of IGF-II on bone cells. This work raises the possibility that this IGFBP may participate in mediating some of the actions of IGF-II.
Bautista
C M
CM
Department of Biochemistry, Loma Linda University, California.
Baylink
D J
DJ
Mohan
S
S
D000595:Amino Acid Sequence; D001667:Binding, Competitive; D001846:Bone Development; D001842:Bone and Bones / Q000737:chemistry / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002455:Cell Division; D017886:Durapatite; D006801:Humans; D006882:Hydroxyapatites / Q000378:metabolism*; D018969:Insulin-Like Growth Factor Binding Proteins; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013002:Somatomedins / Q000378:metabolism
D002352:Carrier Proteins; D006882:Hydroxyapatites; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II; D017886:Durapatite