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A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

CEBPB is an intronless gene and its protein is a bZIP transcription factor which can bind as a homodimer to certain DNA regulatory regions. CEBPB can also form heterodimers with the related proteins CEBP-alpha, CEBP-delta, and CEBP-gamma. CEBPB is important in the regulation of genes involved in immune and inflammatory responses and has been shown to bind to the IL-1 response element in the IL-6 gene, as well as to regulatory regions of several acute-phase and cytokine genes. In addition, CEBPB can bind the promoter and upstream element and stimulate the expression of the collagen type I gene.

GDF15 is part of the TGF-Beta superfamily that is involved in regulating inflammatory and apoptotic pathways in injured tissues and throughout disease processes. GDF15 is most abundant in the liver. Its expression in liver can be considerably up-regulated in during injury of organs such as liver, kidney, heart and lung. GDF-15 promotes proliferation or growth arrest and differentiation due to differences in cellular differentiation. GDF15 prevents apoptosis in cerebellar granule neurons by activating Akt and inhibiting endogenously active ERK. GDF15 is a novel autocrine/endocrine factor that antagonizes the hypertrophic response and loss of ventricular performance.

IGFBP5 is a member of the insulin-like growth factor binding protein (IGFBP) family and encodes a protein with an IGFBP domain and a thyroglobulin type-I domain. The protein forms a ternary complex with insulin-like growth factor acid-labile subunit (IGFALS) and either insulin-like growth factor (IGF) I or II. In this form, it circulates in the plasma, prolonging the half-life of IGFs and altering their interaction with cell surface receptors. Alternate transcriptional splice variants, encoding different isoforms, have been characterized.

Pleiotrophin (Osteoblast-Specific Factor-1, OSF-1) contains 136 amino acid residues. The sequence is very rich in cationic amino acids (24% of the residues); lysine cluster sequences are found in the N-terminal and C-terminal ends of the structure.
The OSF-1 gene was shown by Northern blotting analysis to be expressed in mouse calvarial osteoblast-enriched cells and in mouse brain tissues, but not in thymus, spleen, kidney, liver, lung, testis or heart. Pleiotrophin has the ability to promote adhesion, migration, expansion, and differentiation of human osteoprogenitor cells. In addition to certain types of cancer, the embryonic growth and differentiation factor pleiotrophin is found also in adults in inflammatory diseases. In osteoarthritis, pleiotrophin is especially expressed in early stages, and its concentrations in the synovial fluid could serve as a marker for the progress of the disease. Pleitrophin might be involved in cartilage repair in osteoarthritis, in particular, in earlier stages.

Thrombopoietin is a glycoprotein hormone produced mainly by the liver and the kidneyt hat regulates the production of platelets by the bone marrow. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that fragment into large numbers of platelets.

POU5F1 is a homeodomain transcription factor of the POU family, expressed in embryonic stem (ES) cells and embryonic carcinoma (EC) cells.POU5F1 is significantly involved in the signaling pathway for maintaining self-renewal and pluripotency of ES cells. POU5F1 has 2 distinct DNA binding domains which independently bind half-sites of the canonical octamer motif. This flexibility allows POU5F1 to bind with distinct DNA motifs by forming heterodimers with other transcription factors or by forming homodimers in several conformations. Human POU5F1 contains a 75aa POU specific (POUS) domain and a 60aa POU-Homeo-(POUH) domain connected by a linker region. The Human POU5F1 specifically interacts with Octamer motif ATGCAAAT. In addition, 2 proline-rich domains in the N-terminal and C-terminal regions are vital for POU5F1 transactivation. POU5F1 regulates a number of target genes and has been shown to work jointly with other transcription factors including Sox2 as well as Nanog to sustain stem cell potency and self-renewal.

FIAF (fasting-induced adipose factor) a.k.a ANGPTL4 or PGAR or HFARP is an adipocytokine up-regulated by fasting, by peroxisome proliferator-activated receptor agonists, and by hypoxia. ANGPTL4 is found in human and mouse blood plasma both as a native protein and in a truncated form. In human white adipose tissue and SGBS adipocytes, only the native form of ANGPTL4 could be detected, whereas in mice the differentiation of mouse 3T3-L1 adipocytes is associated with the production of truncated ANGPTL4. However, the truncated ANGPTL4 is produced by human liver. In human blood plasma FIAF is mainly presented in a truncated form (FIAF-S2), whose levels treatment increases (as shown by experimental data). There is an inter individual variation in ANGPTL4 levels of both the truncated and the native form, however those levels were not influenced by prolonged semistarvation and are not associated with body mass index.

GDF-5 is a member of the bone morphogenetic protein (BMP) family and the TGF-beta superfamily. This group of proteins is characterized by a polybasic proteolytic processing site which is cleaved to produce a mature protein containing seven conserved cysteine residues. The members of this family are regulators of cell growth and differentiation in both embryonic and adult tissues. Mutations in this gene are associated with acromesomelic dysplasia, Hunter-Thompson type; brachydactyly, type C; and chondrodysplasia, Grebe type. These associations confirm that the gene product plays a role in skeletal development.

Granulocyte Colony Stimulating Factor is a growth factor and/or cytokine produced by the endothelium, macrophages and a number of other immune cells. GCSF stimulates the bone marrow to produce granulocytes and also to stimulate the survival, proliferation, differentiation and function of neutrophil granulocyte progenator cells and mature neutrophils.

The 26S proteasome is a multicatalytic proteinase complex with a well ordered structure composed of two complexes- a 20S core and a 19S regulator. PSMD11 is a non-ATPase subunit of the 19S regulator. The 20S core is composed of four rings of 28 non-identical subunits; two rings are composed of 7 alpha subunits and two rings are composed of 7 beta subunits. The 19S regulator is composed of a base that contains six ATPase subunits and two non-ATPase subunits, and a lid that contains up to ten non-ATPase subunits. Proteasomes are spread throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An indispensable function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides.

Transcription factor MafG (MAFG) is a member of the Maf family. Given that they lack a putative transactivation domain, the small Mafs act as transcriptional repressors when they dimerize amongst themselves. Nevertheless, they seem to function as transcriptional activators by dimerizing with other (generally larger) basic-zipper proteins and engaging them to specific DNA-binding sites. Small Maf proteins heterodimerize with Fos and may function as competitive repressors of the NF-E2 transcription factor.

TGFBR1 is a single-pass type 1 membrane protein which is a part of the TGFB receptor subfamily and the protein kinase superfamily. TGFBR1 is a secreted protein that performs many cellular functions such as the control of cell growth, cell differentiation, cell proliferation and apoptosis. TGFBR1 also controls the immune system and shows different activities on various types of cell, or cells at different developmental stages.

PRTN3 is a polymorphonuclear leukocyte serine protease which degrades elastin, fibronectin, laminin, vitronectin, and collagen types I, III, and IV (in vitro) and causes emphysema once managed by tracheal insufflation to hamsters.

NT3 a member of the neurotrophin family, that controls survival and differentiation of mammalian neurons. This protein is closely related to both nerve growth factor and brain-derived neurotrophic factor. It may be involved in the maintenance of the adult nervous system, and may affect development of neurons in the embryo when it is expressed in human placenta. NTF3-deficient mice generated by gene targeting display severe movement defects of the limbs. The mature peptide of this protein is identical in all mammals examined including human, pig, rat and mouse.

NADH Dehydrogenase1 Alpha Subcomplex 4 (NDUFA4) is a member of the complex I 9kDa subunit family. Mammalian complex I of mitochondrial respiratory chain is comprised of 45 different subunits. NDUFA4 protein has NADH dehydrogenase activity and oxidoreductase activity. NDUFA4 transfers electrons from NADH to the respiratory chain. The immediate electron acceptor for the NDUFA4 enzyme is assumed to be ubiquinone.

Glycoprotein-9 (GP9) is a small membrane glycoprotein found on the surface of human platelets. GP9 forms a one to one noncovalent complex with glycoprotein Ib, a platelet surface membrane glycoprotein complex which functions as a receptor for von Willebrand factor. The complete receptor complex includes noncovalent association of the alpha and beta subunits with the protein and platelet glycoprotein V. GP9 gene defects cause the Bernard-Soulier syndrome, aka giant platelet disease whose patients have unusually large platelets and have a clinical bleeding tendency.

Chondrolectin (CHODL) is a type I membrane protein with a carbohydrate recognition domain characteristic of C-type lectins in its extracellular portion. In other proteins, this domain is involved in endocytosis of glycoproteins and exogenous sugar-bearing pathogens. The CHODL protein localizes mainly to the perinuclear region.

Clusterin also named Apolipoprotein J (APO-J) is a 75-80 kD disulfide-linked heterodimeric protein containing about 30% of N-linked carbohydrate rich in sialic acid but truncated forms targeted to the nucleus have also been identified.
The precursor polypeptide chain is cleaved proteolytically to remove the 22-mer secretory signal peptide and subsequently between residues 227/228 to generate the a and b chains. These are assembled in anti-parallel to give a heterodimeric molecule in which the cysteine-rich centers are linked by five disulfide bridges and are flanked by two predicted coiled-coil a-helices and three predicted amphipathic a-helices.
Across a broad range of species clusterin shows a high degree of sequence homology ranging from 70% to 80%. It is nearly ubiquitously expressed in most mammalian tissues and can be found in plasma, milk, urine, cerebrospinal fluid and semen.
It is able to bind and form complexes with numerous partners such as immunoglobulins, lipids, heparin, bacteria, complement components, paraoxonase, beta amyloid, leptin and others. Clusterin has been ascribed a plethora of functions such as phagocyte recruitment, aggregation induction, complement attack prevention, apoptosis inhibition, membrane remodeling, lipid transport, hormone transport and/or scavenging, matrix metalloproteinase inhibition.
A genuine function of clusterin has not been defined. One tempting hypothesis says that clusterin is an extracellular chaperone protecting cells from stress induced insults caused by degraded and misfolded protein precipitates.
Clusterin is up- or down regulated on the mRNA or protein level in many pathological and clinically relevant situations including cancer, organ regeneration, infection, Alzheimer disease, retinitis pigmentosa, myocardial infarction, renal tubular damage, autoimmunity and others.

Zinc Finger HIT-Type Containing 3 (ZNHIT3) which contains one HIT-type zinc finger, requires the presence of thyroid hormone for its interaction. Thyroid receptor interacting proteins particularly interact with the ligand binding domain of the thyroid receptor (TR).

YY1 Transcription Factor, also known as YY1, is a part of the GLI-Kruppel class of zinc finger proteins. YY1 has a positive and negative effect on a various cellular and viral genes by binding to sites overlapping the transcription start site. YY1 leads histone deacetylases and histone acetyltransferases to a promoter in order to activate or repress the promoter.

ADP-ribosylation factor-like 14 (ARL14) is a developmentally regulated member of the ADP-ribosylation factor/ARF-like protein (ARF/ARL) family of Ras-related GTPases. ARL14 is GTPase which recruits MYO1E to MHC class II-containing vesicles via the effector protein C11orf46/ARF7EP and thus controls the movement of these vesicles along the actin cytoskeleton in dendritic cells. MHC-II transport was controlled by the GTPase ARL14/ARF7, which recruits the motor myosin 1E via an effector protein ARF7EP.

A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

The somatomedins, or insulin-like growth factors (IGFs), comprise a family of peptides that play important roles in mammalian growth and development. IGF1 mediates many of the growth-promoting effects of growth hormone (GH; MIM 139250). Early studies showed that growth hormone did not directly stimulate the incorporation of sulfate into cartilage, but rather acted through a serum factor, termed 'sulfation factor,' which later became known as 'somatomedin' (Daughaday et al., 1972). Three main somatomedins have been characterized: somatomedin C (IGF1), somatomedin A (IGF2; MIM 147470), and somatomedin B (MIM 193190) (Rotwein, 1986; Rosenfeld, 2003).