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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.

LIN28 plays an important role as a 'translational enhancer', leading specific mRNAs to polysomes and therefore increasing the competence of protein synthesis. LIN28 is a marker of undifferentiated human embryonic stem cells and it enhances the efficiency of the formation of induced pluripotent stem (iPS) cells from human fibroblasts. LIN28 binds to the let-7 pre-miRNA and blocks production of the mature let-7 microRNA in mouse embryonic stem cells. Overexpression of LIN28 is associated with human germ-cell tumors.

Histrelin is a hormone similar to one normally released from the hypothalamus gland in the brain. Histrelin works by decreasing the amount of estrogen and testosterone in the blood. Suppressing estrogen can cause thinning of the bones or slowing of their growth. Histrelin acetate is a potent LHRH agonist which stimulates LH and FSH release and inhibits the actions of sex steroids on the male and female reproductive tracts. After a transient increase, continuous administration results in down regulation of LH and FSH levels followed by a suppression of ovarian and testicular steroid biosynthesis. Histrelin potency in vivo and in vitro is similar to that of the D-Trp6-containing analog. Especially because of its high water solubility and greater lipophilic character, it appears promising for clinical application.

Human Secretin stimulates the secretion of bicarbonate by the pancreas and inhibits the production of gastrin and acid production in the stomach. It also potentiates the release of digestive enzymes from the pancreas triggered by cholecystokinin.

Heat-stable enterotoxins (STa) are small, cysteine-rich peptides secreted by Escherichia coli that are able to induce diarrhea through the stimulation of an intestine-specific receptor-guanylyl cyclase known as STaR. Binding of STa to STaR induces a dramatic increase in the cGMP content of the cell; the increase, in turn, inhibits salt absorption and stimulates chloride secretion. This imbalance of ions is accompanied by a massive accumulation of water in the gut that gives rise to the diarrhea and dehydration characteristic of enterotoxin activity. The identification of a receptor for STa on intestinal brush border membranes suggested the existence of an endogenous activator, described guanylin, a 15-amino acid peptide purified from rat small intestine, as a potential ligand for the STaR. This peptide shares sequence similarity with STa; see also uroguanylin. The molecular cloning of the human and mouse cDNAs encoding guanylin was reported. The sequences demonstrated that guanylin is present at the C-terminal end of a larger precursor protein. Expression in mammalian cells indicated that the 94- amino acid proguanylin is inactive. The biologically active guanylin can be released by either chemical or enzymatic treatment of proguanylin. By Northern blot analysis and in situ hybridization, showed that expression of guanylin mRNA is restricted to cells of the intestinal epithelium, specifically the Paneth cells at the base of the small intestinal crypts. These results demonstrate that guanylin is an endogenous activator of STaR isolated a cDNA encoding an apparent precursor of guanylin from a human intestinal cDNA library. The mRNA was expressed at high levels in human ileum and colon. In the mouse, interspecific backcross analysis used to map the Guca2 gene to the distal half of mouse chromosome 4 in a region of homology with human chromosome 1p. By fluorescence in situ hybridization mapped the GUCA2 gene to human 1p35-p34 Guanylin is thought to modulate intestinal water/electrolyte transport in a paracrine mode reported the nucleotide sequence of the gene, the characteristics of its circulating molecular form, and its localization in enterochromaffin cells of the gut. The gene, approximately 2.6 kb in size, consists of 3 exons interrupted by 2 introns. The hormonal form of guanylin is a 94-amino acid peptide with a molecular mass of 10.3 kDa. Guanylin is synthesized by gut enterochromaffin cells as a prohormone of 115 amino acids and is processed to the molecular form of 94 amino acids circulating in the blood.

Glycinin Ara h 3 is a seed storage protein, 11 S globulin and trypsin inhibitor from peanut. Each subunit of the hexamer is composed of an acidic and a basic chain derived from a single precursor and linked by a disulfide bond. Ara h 3 and Ara h 4 are isoforms. Glycinin is the source of sulfur-containing amino acids in seed meals and it exists in the seeds of many leguminous and non-leguminous plants.

Fractalkine soluble form is chemotactic for t-cells and monocytes, but not for neutrophils. Fractalkine membrane-bound form promotes adhesion of those leukocytes to endothelial cells. Fractalkine regulates leukocyte adhesion and migration processes at the endothelium and binds to CX3CR1. Natural Human Fractalkine is produced as a long protein (373-amino acid) with an extended mucin-like stalk and a chemokine domain on top. The mucin-like stalk permits it to bind to the cell surface. Fractalkine gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.

Clathrin, light chain A (CLTA) is a member of the clathrin family. Clathrin, which is a large, soluble protein, is comprised of heavy and light chains. CLTA is one of 2 clathrin light chain proteins which are supposed to function as regulatory elements. CLTA is a key cytosolic coat protein in pits and vesicles originating from the plasma membrane and the trans-Golgi network. In receptor-mediated endocytosis, receptor proteins are encapsulated by Clathrin-coated vesicles.

Cystatins are a superfamily of cysteine proteinase inhibitors found in both plants and animals. They comprise a group of proteinase inhibitors, widely distributed in tissues and body fluids, and form tight complexes with cysteine proteases such as cathepsin B, H, L and S. Cystatin C, a secreted molecule of this family, is of interest from biochemical, medicine and evolutionary points of view. Cystatin C is increased in patients with malignant diseases, and is related to the insufficiency of renal function and appears to be a better marker than creatinine. On the other hand, low levels of cystatin C involve cause the breakdown of the elastic laminae and subsequently, the atherosclerosis and abdominal aortic aneurysm.

Insulin decreases blood glucose concentration. it increases cell permeability to monosaccharides, amino acids and fatty acids. it accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver.

Chromgranin-A is part of the neuroendocrine secretory protein family. CHGA is located in secretory vesicles of neurons and endocrine cells. Chromgranin-A is a precursor to three biologically active peptides; vasostatin, pancreastatin, and parastatin. These peptides act as autocrine or paracrine negative modulators of the neuroendocrine system. Other peptides, including chromostatin, beta-granin, WE-14 and GE-25, are also derived from the full-length protein. Chromgranin-A has numerous biological activities on some tissues and organs and exerts a large spectrum of homeostatic actions, including antifungal and antimicrobial effect, modulation of cell adhesion, and inhibition of parathyroid hormone secretion.

Myozenin 1 (MYOZ1) is a member of the myozenin family. MYOZ1 is mostly expressed in the skeletal muscle. Members of the myozenin family act as calcineurin-interacting proteins which helps tether calcineurin to the sarcomere of cardiac and skeletal muscle. The myozenin family plays a significant role in modulation of calcineurin signaling.

NCALD belongs to the neuronal calcium sensor (NCS) family. NCALD is cytosolic at inactive calcium levels; but, high intracellular calcium levels induce a conformational transformation which exposes the myristoyl group, causing protein association with membranes and partial co-localization with the perinuclear trans-golgi network. NCALD protein is a regulator of signal transduction by G protein-coupled receptor.

Fractalkine soluble form is chemotactic for t-cells and monocytes, but not for neutrophils. Fractalkine membrane-bound form promotes adhesion of those leukocytes to endothelial cells. Fractalkine regulates leukocyte adhesion and migration processes at the endothelium and binds to CX3CR1. Natural Human Fractalkine is produced as a long protein (373-amino acid) with an extended mucin-like stalk and a chemokine domain on top. The mucin-like stalk permits it to bind to the cell surface. Fractalkine gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.

ER Lipid Raft Associated 2 (ERLIN2) is a domain-containing protein which is a member of the band 7/mec-2 family. ERLIN2 is a ubiquitously expressed 339 amino acid protein.ERLIN2 which is localized to the lipid raft-like domains in the membrane of the endoplasmic reticulum (ER), plays a key role in the ER-associated degradation (ERAD) pathway that eliminates metabolically regulated and abnormal proteins from the ER.

Human Cystatin A (CSTA or Stefin A) belongs to family 1 of the cystatin superfamily, which is characterized by the lack of disulphide bonds and carbohydrates. CSTA is an intracellular inhibitor regulating the activities of cysteine proteases of the papain family such as Cathepsins B, H and L. Cystatin A has also been implicated in several disease states. Because of altered proteolytic state in cancer progression, CSTA may have a role in the proteolitic pathways.

Nucleolin (NCL) which is a eukaryotic nucleolar phosphoprotein, involved in the synthesis and maturation of ribosomes. Nucleolin is the key nucleolar protein of growing eukaryotic cells. NCL is found linked with intranucleolar chromatin and pre-ribosomal particles. NCL induces chromatin decondensation by binding to histone H1. Nucleolin is assumed to have a role in pre-rRNA transcription and ribosome compilation. Nucleolin may also have a role in the process of transcriptional elongation. Nucleolin is located primarily in the dense fibrillar regions of the nucleolus. The Human NCL gene consists of 14 exons with 13 introns and spans approximately 11kb.

Aprotinin inhibits the activity of several proteolytic enzymes such as chymotrypsin, kallikrein, plasmin and trypsin. Aprotinin is present in blood and in most tissues, with a high concentration in lung. Aprotinin inhibits pro-inflammatory cytokine release and maintains glycoprotein homeostasis. In platelets, aprotinin reduces glycoprotein loss (e.g., GpIb, GpIIb/IIIa), while in granulocytes it prevents the expression of pro-inflammatory adhesive glycoproteins (e.g., CD11b).

Fractalkine soluble form is chemotactic for t-cells and monocytes, but not for neutrophils. Fractalkine membrane-bound form promotes adhesion of those leukocytes to endothelial cells. Fractalkine regulates leukocyte adhesion and migration processes at the endothelium and binds to CX3CR1. Natural Human Fractalkine is produced as a long protein (373-amino acid) with an extended mucin-like stalk and a chemokine domain on top. The mucin-like stalk permits it to bind to the cell surface. Fractalkine gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.

Frataxin is a mitochondrial iron binding protein that is part of the FRATAXIN family. Frataxin functions in regulating mitochondrial iron transport and respiration. The expansion of intronic trinucleotide repeat GAA results in Friedreich ataxia. Frataxin plays a role in iron homeostasis. Frataxin is an anti-apoptotic protein which prevents mitochondrial damage and reactive oxygen species (ROS) production.

Eosinophil lysophospholipase (CLC) acts on biological membranes to regulate the multifunctional lysophospholipids. CLC is a lysophospholipase expressed in eosinophils and basophils. CLC hydrolyzes lysophosphatidylcholine to glycerophosphocholine and a free fatty acid. The CLC protein may possess carbohydrate or IgE-binding activities. CLC is both structurally and functionally related to the galectin family of beta-galactoside binding proteins. CLC may be linked with inflammation and some myeloid leukemias.

Crk-like protein (CRKL) is a protein kinase containing SH2 and SH3 (src homology) domains which activates the RAS and JUN kinase signaling pathways and transforms fibroblasts in a RAS-dependent manner. CRKL is a substitute of the BCR-ABL tyrosine kinase, it also has a role in fibroblast transformation by BCR-ABL, and has oncogenic potential.

Recoverin is a member of the recoverin family of neuronal calcium sensors. Recoverin is a heterogeneously acylated calcium-binding and intracellular signal transduction 23kDa protein in the photoreceptor cells of retina. Recoverin contains four EF-hands, of which two bind Ca. Ca-induced extrusion of the acyl group from a hydrophobic cleft in the protein drives the translocation of recoverin from solution to the disc membrane. Recoverin may prolong the termination of the phototransduction cascade in the retina by blocking the phosphorylation of photo-activated rhodopsin. Recoverin plays a key role in the inhibition of rhodopsin kinase, a molecule that regulates the phosphorylation of rhodopsin. This in due course controls the ability of the eye to adapt to, and recover from, exposure to the presence of light. Recoverin is a detectable serologic protein that is expressed in patients with cancer-associated retinopathy, a paraneoplastic syndrome.

Fractalkine soluble form is chemotactic for t-cells and monocytes, but not for neutrophils. Fractalkine membrane-bound form promotes adhesion of those leukocytes to endothelial cells. Fractalkine regulates leukocyte adhesion and migration processes at the endothelium and binds to CX3CR1. Fractalkine gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.