Adiponectin (ACRP30) Mouse Active Protein

Function: Important adipokine involved in the control of fat metabolism and insulin sensitivity, with direct anti-diabetic, anti-atherogenic and anti-inflammatory activities. Stimulates AMPK phosphorylation and activation in the liver and the skeletal muscle, enhancing glucose utilization and fatty-acid combustion. Antagonizes TNF-alpha by negatively regulating its expression in various tissues such as liver and macrophages, and also by counteracting its effects. Inhibits endothelial NF-kappa-B signaling through a cAMP-dependent pathway. May play a role in cell growth, angiogenesis and tissue remodeling by binding and sequestering various growth factors with distinct binding affinities, depending on the type of complex, LMW, MMW or HMW. Ref.11 Ref.12 Ref.13 Ref.14 Ref.15

Subunit structure: Homomultimer. Forms trimers, hexamers and 12- to 18-mers. The trimers (low molecular weight complexes / LMW) are assembled via non-covalent interactions of the collagen-like domains in a triple helix and hydrophobic interactions within the globular C1q domain. Several trimers can associate to form disulfide-linked hexamers (middle molecular weight complexes / MMW) and larger complexes (higher molecular weight / HMW). The HMW-complex assembly may rely additionally on lysine hydroxylation and glycosylation. LMW, MMW and HMW complexes bind to HBEGF, MMW and HMW complexes bind to PDGFB, and HMW complex binds to FGF2. Interacts with CTRP9 via the C1q domain (heterotrimeric complex). Ref.14 Ref.15 Ref.16 Ref.17 Ref.18

Subcellular location: Secreted.

Tissue specificity: Synthesized exclusively by adipocytes and secreted into plasma.

Induction: During hormone-induced adipose differentiation and activated by insulin.

Post-translational modification: HMW complexes are more extensively glycosylated than smaller oligomers. Hydroxylation and glycosylation of the lysine residues within the collagene-like domain of adiponectin seem to be critically involved in regulating the formation and/or secretion of HMW complexes and consequently contribute to the insulin-sensitizing activity of adiponectin in hepatocytes. Ref.9 Ref.10 Ref.18O-glycosylated. Not N-glycosylated

By similarity O-linked glycans on hydroxylysine residues consist of Glc-Gal disaccharides bound to the oxygen atom of post-translationally added hydroxyl groups

By similarity. O-linked glycosylation in the N-terminal is disialylated with the structure Neu5Acalpha2->8Neu5Acalpha2->3Gal. Sialylated by alpha 2,8-sialyltransferase III. Ref.9 Ref.10 Ref.18

Miscellaneous: HMW-complex blood contents are higher in females than in males, are increased in males by castration and decreased again upon subsequent testosterone treatment, which blocks HMW-complex secretion.

Sequence similarities: Contains 1 C1q domain.Contains 1 collagen-like domain.