Up date on IGFBP-4: regulation of IGFBP-4 levels and functions, in vitro and in vivo.
Of the six known high affinity insulin-like growth factor binding-proteins (IGFBPs), IGFBP-4 appears to be unique in that it is the only IGFBP that functions mostly like a traditional binding protein. In this regard, none of the IGF independent effects that have been ascribed for other IGFBPs have been described for IGFBP-4. However, recent in vitro and in vivo studies, in particular the recent identification of pregnancy-associated plasma protein-A as a major IGFBP-4 protease, are consistent with the idea that IGFBP-4 is an extremely important component of IGF system in several tissues including gonads and bone. In this review, we have provided an update on IGFBP-4 research and we have summarized our current understanding of the regulation of levels and actions of IGFBP-4 and proteolytic fragments both in vitro and in vivo.
Mazerbourg
Sabine
S
Station INRA de Physiologie de la Reproduction et des Comportements, CNRS UMR 6073, Université François Rabelais de Tours, 37380 Nouzilly, France.
Callebaut
Isabelle
I
Zapf
Jürgen
J
Mohan
Subburaman
S
Overgaard
Michael
M
Monget
Philippe
P
D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D066298:In Vitro Techniques; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000096:biosynthesis* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011266:Pregnancy-Associated Plasma Protein-A / Q000502:physiology; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014158:Transcription, Genetic
D018974:Insulin-Like Growth Factor Binding Protein 4; D011266:Pregnancy-Associated Plasma Protein-A