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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.

Midkine (MK) is the product of a retinoic acid responsive gene, MK, and is a member of a family of heparin binding factors. It contains 121 amino acid residues including 10 conserved cysteine residues, all of which appear to be disulphide linked.
Midkine is expressed during embryogenesis, showing an expression pattern that suggests functions in neurogenesis, cell migration, secondary organogenetic induction, and mesoderm-epithelial interaction.
The widespread downregulation of MK in the adult human is reverted in a number of cancers, in which polypeptides are able to act as both transforming growth factors and promoters of angiogenesis.
Midkine (MK), induces chemotaxis of human neutrophils and was found to trigger mobilization of intracellular calcium of these cells.
Midkine induces histamine release from rat peritoneal mast cells with a rapid response in a dose dependent manner.
Midkine is also a potent stimulator of collagen and glycosaminoglycan synthesis.

S100b is a member of the S100 family of proteins which are a family of EF-hand calcium binding proteins that exist mostly as dimers of the 20 currently identified individual S100 monomers. The S100B homodimer is expressed in cells of the central nervous system, glial cells and in certain peripheral cells e.g. Schwann cells, melanocytes, adipocytes and chondrocytes. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. S100 proteins are involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21; however, S100b is located at 21q22.3. The determination of S100B in serum levels may be used to monitor the extent of brain injury and malignant melanoma. S100b proteins may have a role in Neurite extension, proliferation of melanoma cells, stimulation of Ca2+ fluxes, inhibition of PKC-mediated phosphorylation, astrocytosis and axonal proliferation, and inhibition of microtubule assembly. Chromosomal rearrangements and altered expression of the S100b gene are implicated in several neurological, neoplastic, and other types of diseases, including Alzheimer's disease, Down's syndrome, epilepsy, amyotrophic lateral sclerosis, melanoma, and type I diabetes.

SAR1B is a small GTPase that functions as a homodimer. GTP-Binding Protein SAR1B (SAR1b) is involved in transport from the endoplasmic reticulum to the Golgi apparatus and also in the selection of the protein cargo and the assembly of the COPII coat complex. The SAR1B protein is activated by the guanine nucleotide exchange factor PREB. SAR1B gene defects are a cause of chylomicron retention disease (CMRD), also known as Anderson disease (ANDD).

NEDD8 is part of the ubiquitin family. Human NEDD8 shares 60% amino acid sequence homology to ubiquitin. The NEDD8 system is essential for the regulation of protein degradation pathways involved in cell cycle progression, morphogenesis and tumorigenesis. NEDD8 is involved in cell cycle control and embryogenesis. Covalent attachment to its substrates requires prior activation by the E-1 complex UbE1c- appbp1 and linkage to the E-2 enzyme UbE2m. Attachment of NEDD8 to cullins activates their associated E-3 ubiquitin ligase activity, and thus promotes polyubiquitination and proteasomal degradation of cyclins and other regulatory proteins.

The bone morphogenetic proteins (BMPs) are a family of secreted signaling molecules that can induce ectopic bone growth. Many BMPs are part of the transforming growth factor-beta (TGFB) superfamily. BMPs were originally identified by an ability of demineralized bone extract to induce endochondral osteogenesis in vivo in an extraskeletal site. Based on its expression early in embryogenesis, the BMP encoded by this gene has a proposed role in early development. In addition, the fact that this BMP is closely related to BMP5 and BMP7 has lead to speculation of possible bone inductive activity.

Paralemmin (PALM) belongs to the paralemmin protein family which takes part in plasma membrane dynamics and cell process formation. The product of PALM is related with the cytoplasmic face of plasma membranes and is implicated in plasma membrane dynamics in neurons and other cell types.

Tumor-associated calcium signal transducer 2 (TACSTD2), is a member of to the EPCAM family. TACSTD2 is an intronless gene which encodes a carcinoma-associated antigen. TACSTD2 may act as a growth factor receptor and as a cell surface receptor that transduces calcium signals. Mutations of TACSTD2 have been associated with gelatinous drop-like corneal dystrophy.

The Trefoil Factor peptides (TFF1, TFF2 and TFF3) are stable secretory proteins expressed in the gastrointestinal tract (gastric mucosa), and are involved in intestinal mucosal defense and repair. TFF1 is an essential protein for normal differentiation of the antral and pyloric gastric mucosa and functions as a gastric-specific tumor suppressor gene. TFF1 is a stabilizer of the mucous gel overlying the gastrointestinal mucosa that provides a physical barrier against various noxious agents. TFF1 protects the mucosa from isults, stabilizes the mucus layer, & affects healing of the epithelium. TFF1 is commonly expressed in tumors. TFF1 is related with the cell membrane of MCF-7 cells. High levels of TFF1 and TFF2 are found in serum from inflammatory bowel disease.

Calreticulin 3 (CALR3) belongs to the calreticulin (CRT) family which consists of calcium binding chaperones that are localized to the endoplasmic reticulum or sarcoplasmic reticulum in eukaryotes. CALR3, which is expressed mainly in testis, takes part in protein-folding, oligomeric assembly and quality control in the ER. CALR3 plays an important role as a cancer-testis antigen due to its frequent expression in many cancers.

TGFBI is an extracellular matrix protein induced by transforming growth factor (TGF)-beta 1. TGFBI protein is involved in cell growth, cell differentiation, wound healing and cell adhesion. In addition, some missense mutations of TGFBI were identified in families affected with human autosomal dominant corneal dystrophies. TGFBI gene encodes for a 683 amino-acid protein containing an RGD motif and four internal repeated domains which have highly conserved sequences founded in several species (Fasciclin domain).

Translocase of Inner Mitochondrial Membrane 8 Homolog A (TIMM8A) takes part in the import and insertion of hydrophobic membrane proteins from the cytoplasm into the mitochondrial. TIMM8A plays a role as a chaperone-like protein which protects the hydrophobic precursors from aggregation and leads them through the mitochondrial intermembrane space. TIMM8A is essential for the transfer of beta-barrel precursors from the TOM complex to the sorting and assembly machinery (SAM complex) of the outer membrane. Defects in TIMM8A cause Jensen syndrome. TIMM8A and TIMM13, forms a 70 kDa heterohexamer.

Lymphotoxin alpha, a member of the tumor necrosis factor family, is a cytokine produced by lymphocytes. LTA is highly inducible, secreted, and exists as homotrimeric molecule. LTA forms heterotrimers with lymphotoxin-beta which anchors lymphotoxin-alpha to the cell surface. LTA mediates a large variety of inflammatory, immunostimulatory, and antiviral responses. LTA is also involved in the formation of secondary lymphoid organs during development and plays a role in apoptosis.

GTF2B is one of the ubiquitous factors needed for transcription initiation by RNA polymerase II preinitiation factor. GTF2B localizes to the nucleus where it forms a complex (the DAB complex) with transcription factors IID and IIA. GTF2 plays a role as a bridge between IID, which initially recognizes the promoter sequence, and RNA polymerase II. GTF2B is involved in the selection of the transcription start site.

ST13 is an adaptor protein (co-chaperone) that mediates the association of HSP70 & HSP90 and appears in early receptor complexes. ST13 plays a role in the assembly process of glucocorticoid receptor, which requires the assistance of multiple molecular chaperones. The expression of ST13 is downregulated in colorectal carcinoma tissue signifying that is candidate tumor suppressor gene. Through common binding to both Hsp70 and Hsp90, ST13 functions as an adaptor that can integrate Hsp70 and Hsp90 interactions. The expression of ST13 decreases in colorectal cancer tissue compared with that in adjacent normal tissue. ST13 is mostly expressed in colorectal epithelia and adenocarcinoma cells. ST13 functions to promote the efficiency of glucocorticoid receptor maturation in cells. The expression levels of the ST13 gene were significantly decreased in primary tumors compared with adjacent mucosa.

EPO is a member of the EPO/TPO family and encodes a secreted, glycosylated cytokine composed of 4 alpha helical bundles. EPO is found in the plasma and regulates red cell production by promoting erythroid differentiation and initiating hemoglobin synthesis. EPO also has neuroprotective activity against a variety of potential brain injuries and antiapoptotic functions in several tissue types.

The PARK7 is a ubiquitously expressed protein involved in various cellular processes including spermatogenesis and fertilization, cancer, RNA-binding, androgen-receptor signaling and oxidative stress. Mutations in the PARK7 are the cause of autosomal recessive early-onset Parkinson’s disease 7 (Park7).

CD34 is a single chain transmembrane glycoprotein which is selectively expressed on human lymphoid and myeloid hemapoietic progenitor cells. CD34 has been used to measure angiogenesis, which reportedly predicts tumor recurrence.

KRT18 encodes the type I intermediate filament chain keratin 18. Keratin 18, together with its filament partner keratin 8, are perhaps the most commonly found members of the intermediate filament gene family. They are expressed in single layer epithelial tissues of the body. Mutations in this gene have been linked to cryptogenic cirrhosis. Two transcript variants encoding the same protein have been found for this gene.

Peroxisome proliferators are non-genotoxic carcinogens which are purported to exert their effect on cells through their interaction with members of the nuclear hormone receptor family termed peroxisome proliferators activated receptors (PPARs). Nuclear hormone receptors are ligand-dependent intracellular proteins that stimulate transcription of specific genes by binding to specific DNA sequences following activation by the appropriate ligand. Studies indicate that PPARs are activated by peroxisome proliferators such as clofibric acid, nafenopin, and WY-14,643, as well as by some fatty acids.

CXCL14 is involved in immunoregulatory and inflammatory processes. BRAK protein is structurally related to the CXC (Cys-X-Cys) subfamily of cytokines. CXCL14 displays chemotactic activity for monocytes but not for lymphocytes, dendritic cells, neutrophils or macrophages. CXCL14 is involved in the homeostasis of monocyte-derived macrophages.

Chemokine (C motif) ligand (XCL1) is a small cytokine belonging to the XC chemokine family that is also known as lymphotactin. It is found in high levels in spleen, thymus, intestine and peripheral blood leukocytes, and at lower levels in lung, prostate gland and ovary. Cellular sources for XCL1 include activated thymic and peripheral blood CD8+ T cells. This chemokine attracts T cells. In humans, XCL1 is closely related to another chemokine called XCL2, whose geneis found at the same locus on chromosome 1. XCL1 induces it chemotactic function by binding to a chemokine receptor called XCR1.

Actin is a muscle protein localized in the I band of the myofibrils; acting along with myosin, it is responsible for contraction and relaxation of muscle. Each actin protomer binds one molecule of ATP and has one high affinity site for either calcium or magnesium ions, as well as several low affinity sites. Actin exists as a monomer in low salt concentrations, but filaments form rapidly as salt concentration rises, with the consequent hydrolysis of ATP. It occurs in globular (G-actin) and fibrous (F-actin) forms. Actin is found in all eukaryotic cells (except for nematode sperm). Actin is one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans. Its other functions include cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the establishment and maintenance of cell junctions and cell shape.