Search results

SPINT2 is a transmembrane protein acts as an inhibitor of HGF activator. SPINT2 inhibits plasmin, plasma and tissue kallikrein, and factor XIa. SPINT2 has two extracellular Kunitz domains that inhibit few serine proteases. SPINT2 is assumed tumor suppressor, mutations in SPINT2 leads to a congenital sodium diarrhea.

Energy Homeostasis Associated (ENHO) participates in glucose homeostasis maintenance and lipid metabolism. ENHO is expressed in the liver and the brain. The role of ENHO in obesity or diabetes is studied.

SRP54 is a 54-kDa subunit of the signal recognition particle (SRP), a cytoplasmic ribonucleoprotein complex which leads the translocation of newly synthesized secretory proteins from the polysome to the endoplasmic reticulum. SRP is composed of six polypeptides and a tRNA-like molecule known as 7SL RNA. SRP54 is a GTP-binding protein that directly binds the signal sequences of nascent secretory and membrane proteins. Anti-SRP autoantibodies take place in patients with an autoimmune chronic muscle inflammation called polymyositis. These auto-antibodies predominantly recognize the SRP54 subunit and in addition are able to immunoprecipitate several of the SRP subunits and the RNA component. Nearly 5% of myositis patients are positive for anti-SRP autoantibodies, increasing to 18% in the subgroup of Jo-1 autoantibody-negative patients. The classic 'anti-SRP syndrome' is a severe form of polymyositis in which the myositic inflammation is acute and aggressive onset, with common myalgias and cardiac involvement. Normally there is a poor reaction to therapy with a 5-year survival rate of about 25%.

Erythropoietin receptor, also known as EPOR arbitrates erythropoietin-induced erythroblast proliferation as well as differentiation. During EPO binding, EPOR activates Jak2 tyrosine kinase which activates various intracellular pathways including: Ras/MAP kinase, phosphatidylinositol 3-kinase and STAT transcription factors. Furthermore, stimulated EPOR has a function in erythroid cell survival. Mutations in EPOR may possibly produce erythroleukemia and familial erythrocytosis. In addition, dysregulation of EPOR can affect on the growth of selected tumors.

OTOR proteins is also known as fibrocyte-derived protein (Fdp) and Melanoma inhibitory activity-like (MIAL). Otoraplin is a member of the melanoma-inhibiting activity gene family. Otoraplin is a secreted 16 kDa globular protein that is expressed in the inner ear by periotic mesenchyme and developing and mature fibrocytes. OTOR is highly homologous to MIA/cartilage-derived retinoic acid-sensitive protein (CD-RAP), which is a cartilage-specific protein that is also expressed in malignant melanoma cells. The 111 amino acid mature human otoraplin contains 1 SH3 domain (46 – 107 amino acids) and a Tyr at position 50 that is reportedly sulfated. Otoraplin takes pasrt in the initiation of periotic mesenchyme chondrogenesis.
Otoraplin is secreted through the Golgi apparatus and plays a role in cartilage development and maintenance. A frequent polymorphism in the translation start codon of OTOR can abolish translation and may be associated with forms of deafness.

Hyaluronan And Proteoglycan Link Protein 1, which is also known as HAPLN1 is a part of the HAPLN family.HAPLN1 contains one Ig-like V-type domain and two Link domains. In the extracellular cartilage matrix, HAPLN1 stabilizes the aggregates of proteoglycan monomers by means of hyaluronic acid .

Vitronectin (VTN) which is a part of the pexin family is a cell adhesion and spreading factor found in serum and tissues. VTN interacts with glycosaminoglycans and proteoglycans. VTN inhibits the membrane-damaging effect of the terminal cytolytic complement pathway and binds to numerous serpin serine protease inhibitors. Scientists have been noticed an over expression of VTN, integrins and plasminogen in migrating cells during wound healing.

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.

Thyroglobulin (TG) represents one of the main autoantigenic targets in autoimmune thyroid disease of humans. TG is a large globular dimeric glycoprotein with a total molecular weight of 660 kDa, which occupies a key precursor role in the biosynthesis of the thyroid hormones. Approximately 75% of the total protein content of the thyroid follicle consists of TG. The thyroid gland uses the Thyroglobulin in order to produce the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroglobulin is produced by the thyroid epithelial cells (thyrocytes) which form spherical follicles. Thyroglobulin is subsequently secreted and stored in the follicular lumen.
Patients with Hashimoto's thyroiditis or Graves' disease, frequently develop antibodies against Thyroglobulin. Tg-specific antibodies help in the diagnosis of the above diseases, however they also may be present in apparently healthy euthyroid individuals. Blood Thyroglobulin levels can be used as a tumor marker for certain kinds of thyroid cancer, and the may also be elevated in cases of Graves' disease.

Keratin 8 and 18 (K8/18) are the major components of intermediate filament (IF) proteins of simple or single-layered epithelia.

Prothrombin produced in the liver is a vitamin K-dependent plasma protein. Before prothrombin is secreted into the plasma it goes through post translational modification by vitamin K-dependent carboxylase. The vitamin K-dependent carboxylase convertsprothrombin to 10 glutamic acid residues to gamma carboxyglutamic acid. Prothrombin comprises of 2 kringle regions which are found among residues a.a. 40 & 270 of the mature plasma protein and substitute the growth factor domains located in numerous plasma serine proteases.

Chemokine (C-C motif) ligand 13 (CCL13 / MCP-4) is a small cytokine belonging to the CC chemokine family. The MCP-4 gene is located on human chromosome 17 within a large cluster of other CC chemokines. MCP-4 induces chemotaxis in monocytes, eosinophils, T lymphocytes, and basophils by binding cell surface G-protein linked chemokine receptors such as CCR2, CCR3 and CCR5. Activity of the MCP-4 chemokine has been implicated in allergic reactions such as asthma. MCP-4 can be induced by the inflammatory cytokines interleukin-1 and TNF-a.

Epiregulin is part of the EGF family. Epiregulin functions as a ligand of EGFR, as well as a ligand of most members of the ERBB (v-erb-b2 oncogene homolog) family of tyrosine-kinase receptors.Epiregulin is expressed mostly in the placenta and peripheral blood leukocytes and in specific carcinomas of the bladder, lung, kidney and colon. Epiregulin stimulates the proliferation of keratinocytes, hepatocytes, fibroblasts and vascular smooth muscle cells. Epiregulin inhibits the growth of several tumor-derived epithelial cell lines. Human Epiregulin is initially synthesized as a glycosylated 19.0 kDa transmembrane precursor protein, which is processed by proteolytic cleavage to produce a 6.0 kDa mature secreted sequence.

GH-releasing peptides (GHRPs) are synthetic peptides that like GHRH effect on pituitary somatotrophs to stimulate GH release. The GHRP1 is one of several synthetic met-enkephalin analogs that owns unnatural D-amino acids. They were developed for their growth hormone (GH) releasing activity and called GH secretatogues. They lack opioid activity but are potent stimulators of GH release. These secretatogues are distinct from the growth hormone releasing hormone (GHRH or GHRF) as they share no sequence relation and derive their function through action at a completely different receptor, the ghrelin receptor.

Members of the Rho (or ARH) protein family and other Ras-related small GTP-binding proteins are involved in various cellular procedures, such as cell cytoskeletal organization, secretion, proliferation, and signaling. The GTPBPs are active only in the GTP-bound state. At least 3 types of proteins firmly regulate cycling between the GTP-bound and GDP-bound states: GDP-dissociation inhibitors (GDIs), GTPase-activating proteins (GAPs) and guanine nucleotide-releasing factors (GRFs). ARHGDIB and the other GDIs lower the level of GDP dissociation from Ras-like GTPases.

Platelet factor-4 is a 70-amino acid protein that is released from the alpha-granules of activated platelets and binds with high affinity to heparin. Its major physiologic role appears to be neutralization of heparin-like molecules on the endothelial surface of blood vessels, thereby inhibiting local antithrombin III activity and promoting coagulation. As a strong chemoattractant for neutrophils and fibroblasts, PF4 probably has a role in inflammation and wound repair. Oncostatin-A is a member of the CXC chemokine family. Human PF4 is used for the proof of heparin-induced thrombocytopenia. Furthermore it is used as an inhibitor in the angiogenesis during tumor therapy.

Leptin takes an important part in the regulation of energy balance and body weight control.After entering the circulation, Leptin binds LEPRwhich results in the activation of several major signalling pathways. In the hypothalamus Leptin acts as an appetite-regulating factor that induces a decrease in food intake and an increase in energy consumption and also regulates bone mass and secretion of hypothalamo-pituitary-adrenal hormones. In the periphery, increases basal metabolism, regulates pancreatic beta-cell function and insulin secretion and affects innate and adaptive immunity.

Histone is vastly alkaline protein exists in eukaryotic cell nuclei which set and direct the DNA into structural units named nucleosomes. 5 key families of histones are: H1/H5, H2A, H2B, H3, including H4. The core histones are H2A, H2B, H3 and H4, whereas histones H1/H5 are identified as the linker histones. Moreover the dynamics of chromatin structure depend on posttranslational modification of histones in addition to the appearance of different histone variants. Histone H3 as well as H4 are modified covalently at several residues. The histone code is constitute by these and the H2A/H2B modifications.

Plasminogen activator inhibitor-1 is the principal inhibitor of tissue plasminogen activator(tPA) and urokinase(uPA), the activators of plasminogenand hence fibrinolysis(the physiological breakdown of blood clots). It is a serine protease inhibitor(serpin) protein (SERPINE1). The other PAI, plasminogen activator inhibitor-2(PAI-2) is secreted by the placentaand only present in significant amounts during pregnancy. In addition, protease nexinacts as an inhibitor of tPA and urokinase. PAI-1, however, is the main inhibitor of the plasminogen activators.

Polcalcin Aln g 4 (Aln G 4.0101) causes an allergic reaction in humans.

Native human C4 is aglycosylated polypeptide containing 3 disulfide-linked chains. C4 is essential to the activation of both thelectin and the classical pathways of complement activation.Initiation of each pathway generates proteolytic enzyme complexes which are bound to the target surface. These enzymes cleave a peptide bond in C4 releasing the anaphylatoxin C4a and activating C4b. Like C3, the thioester of metastable C4b is highly reactive and is capable of reacting and covalently coupling C4b to amino or hydroxyl groups on the target surface. C4A and C4B are 2 variants of C4 that are common in manwhereas, in animals who have only 1 type usually have C4B.

Listeriolysin O (aka LLO) is a hemolysin produced by Listeria monocytogenes bacteria, the pathogen responsible for causing listeriosis. The toxin may be regarded as a virulence factor, since it is crucial for the virulence of L. monocytogenes. LLO is a single polypeptide protein encoded by the hlyA gene and composed of 529 residues. LLO is a thiol-activated cholesterol-dependent pore forming toxin protein; therefore, it is activated by reducing agents and inhibited by oxidizing agents. Still, LLO differs from other thiol-activated toxins, as its cytolytic activity is maximized at a pH of 5.5. Inside the acidic phagosomes (average pH ~ 5.9) of cells that have phagocytosed L. monocytogenes, LLO is selectively activated by maximizing activity at a pH of 5.5. Following the phagosome lysis by LLO, the bacterium breaks out into the cytosol, where it is able to grow intracellularly, and the toxin has reduced activity in the more basic cytosol. Thus, LLO permits L. monocytogenes to break out from the phagosomes into the cytosol without harming the plasma membrane of the infected cell, which allows the bacteria to live intracellularly, where they are sheltered from extracellular immune system factors such as the complement system and antibodies. LLO also brings about dephosphorylation of histone H3 and deacetylation of histone H4 in the early phases of infection, before entry of L. monocytogenes into the host cell. The pore-forming activity is not implicated in causing the histone modifications. The modifications of the histones affect the down regulation of genes encoding proteins involved in the inflammatory response. Therefore, LLO may be significant in subverting the host immune response to L. monocytogenes. At its NH2-terminus it possesses a 25 residues long typical signal sequence excited during the secretion process. Moreover, in its NH2-terminus there is also a 19 amino acids PEST- like sequence that may target this toxin for degradation. The PEST-like sequence found in LLO and is considered crucial for virulence, given that mutants lacking the sequence lysed the host cell. Nevertheless, contrary to PEST's supposed role in protein degradation, evidence implies that the PEST-like sequence may control LLO production in the cytosol rather than increase degradation of LLO.

NPPC is proteolytically managed to create a secreted hormone of the natriuretic peptide family. NPPC is vasoactive and natriuretic and controls the evolution and differentiation of cartilaginous growth plate chondrocytes.