IGFBP-6 is a 30 kDa secreted protein, and unlike other IGFBPs, has a significantly higher affinity (~70-100-fold) for IGF-2 than IGF-1 [15, 16].
During development, IGFBP-6 is expressed abundantly in developing muscle cells and is also required for myogenesis .
Phosphorylation and O-glycosylation are also involved in affinity changes of IGFBP-6
and cause inhibition of IGF-II action on target cells [26, 27].
La eficacia de los IGF en el ambito celular esta modulada por las proteinas de union al IGF (IGFBP), proteinas homologas de las cuales se han descrito desde IGFBP-1 hasta IGFBP-6
. Las observaciones de Hajjar y otros autores sobre IGFBP se resumen en la tabla 2 (61).
The actions of IGFs are mainly mediated via IGF receptor 1 (IGFR-1) and are modulated by six binding proteins (IGFBPs), designated as IGFBP-1 to IGFBP-6
So far, five IGFBPs (IGFBP-1, 2, 3, 4, 5) and low-affinity IGFBP-7 are identified in NCBI chicken genome (build 2.1), since no IGFBP-6
gene homologue has been identified for chickens.
They also identified linkages to genes in the RA-signaling pathway (IGFBP-3 and IGFBP-6
), but again, not the specific genes used in Figure 2.
Insulin-like growth factors (IGF-I, free IGF-I, and IGF-II) and insulin-like growth factor binding proteins (IGFBP-2, IGFBP-3, IGFBP-6
, and ALS) in blood circulation.
<0.5 0.5-1.0 1-10 10-100 >100 (ng/ml) EGF BMP-7 Angiogenin PECAM-1 VCAM-1 FGF-7 EG-VEGF BDNF ANG-1 Angiostatin GDNF GDF-15 bFGF E-cadherin L-selectin GH Tie-2 BMP-5 E-selectin HB-EGF VEGF EGF R ICAM-2 HGF VEGF R1 FGF-4 IGFBP-2 NGF R VEGF-C IGFBP-1 IGFBP-3 PIGF Insulin IGFBP-4 SCF PDGF-AA IGFBP-6
SDF-1b PDGF-BB MCSF R TGFa PF4 PAI-1 TGFb2 TGFb1 PDGF Rb TGFb3 TIMP-1 PDGF-AB VEGF R3 VEGF R2 SCF R OPG VEGF-D OPN
The best nontarget predictors included Bdnf, Actc1, c-myc single-strand-binding protein, Igfbp-6
, and integrin beta4.
, a member of the IGF binding protein family, is expressed abundantly in developing muscle cells and is required for myogenesis .
Moreover, IGF-2 specific binding protein, IGFBP-6
, is expressed during embryonic development in many different tissues including the ossifying bones of the cranium, myoblasts, and the motor neurons of the spinal cord .