Adiponectin (ADIPOQ) HUMAN Active Protein

This gene is expressed in adipose tissue exclusively. It encodes a protein with similarity to collagens X and VIII and complement factor C1q. The encoded protein circulates in the plasma and is involved with metabolic and hormonal processes. Mutations in this gene are associated with adiponectin deficiency. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Apr 2010]

adiponectin: 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. 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 aditionally 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 CTRP9A via the C1q domain (heterotrimeric complex). Synthesized exclusively by adipocytes and secreted into plasma.

Protein type: Endoplasmic reticulum; Secreted, signal peptide; Secreted; Hormone

Chromosomal Location of Human Ortholog: 3q27

Cellular Component: extracellular space; collagen; cell surface; endoplasmic reticulum; extracellular region

Molecular Function: identical protein binding; protein binding; protein homodimerization activity; hormone activity; cytokine activity; sialic acid binding; receptor binding

Biological Process: circadian rhythm; negative regulation of MAP kinase activity; negative regulation of phagocytosis; negative regulation of smooth muscle cell proliferation; negative regulation of hormone secretion; positive regulation of cellular protein metabolic process; membrane hyperpolarization; response to glucocorticoid stimulus; negative regulation of smooth muscle cell migration; glucose homeostasis; negative regulation of granulocyte differentiation; positive regulation of interleukin-8 production; positive regulation of glucose import; negative regulation of gluconeogenesis; response to glucose stimulus; adiponectin-mediated signaling pathway; negative regulation of protein amino acid autophosphorylation; negative regulation of blood pressure; negative regulation of cell migration; response to nutrient; protein homooligomerization; generation of precursor metabolites and energy; positive regulation of I-kappaB kinase/NF-kappaB cascade; negative regulation of heterotypic cell-cell adhesion; positive regulation of signal transduction; glucose metabolic process; negative regulation of I-kappaB kinase/NF-kappaB cascade; negative regulation of tumor necrosis factor production; negative regulation of fat cell differentiation; negative regulation of synaptic transmission; response to sucrose stimulus; membrane depolarization; positive regulation of peptidyl-tyrosine phosphorylation; positive regulation of fatty acid metabolic process; response to ethanol; fatty acid beta-oxidation; cellular response to insulin stimulus; negative regulation of macrophage differentiation; negative regulation of low-density lipoprotein receptor biosynthetic process; negative regulation of inflammatory response; response to hypoxia; brown fat cell differentiation; fatty acid oxidation; response to activity; positive regulation of protein amino acid phosphorylation; negative regulation of transcription, DNA-dependent; positive regulation of myeloid cell apoptosis; positive regulation of blood pressure

Disease: Adiponectin, Serum Level Of, Quantitative Trait Locus 1