Other Proteins

CD31, also known as platelet endothelial cell adhesion molecule-1 (PECAM-1), is a 130 kDa heavily glycosylated transmembrane protein belonging to the immunoglobulin (Ig) superfamily of cell adhesion molecules. CD31 is highly expressed on endothelial cells and at a lower level on platelets, granulocytes, macrophages, dendritic cells, T and B cells, and natural killer (NK) cells. It is involved in cell adhesion and is required for transepithelial migration of leukocytes (TEM). CD31 is composed of an extracellular domain (ECD) of 574 amino acids containing six Ig-like domains, a transmembrane domain, and a 118 aa cytoplasmic domain. The latter undergoes alternative splicing which generates multiple isoforms showing altered adhesive properties compared to full length CD31. The human CD31 ECD shares 63% and 61% aa sequence identity with mouse and rat CD31, respectively. CD31 acts as a homophilic receptor through its extracellular domain and is involved in downstream signaling via its cytopl

Chromogranin A (CgA), also known as pituitary secretory protein I (SP-I), is a member of the granin family of regulated secretory proteins. CgA shares several protein characteristics common to the granin family: acidic isoelectric point, the capacity to bind calcium ions, the ability to form aggregates and multiple dibasic cleavage sites. Mature human CgA is 439 amino acids (aa) and contains 10 dibasic, proteolytic cleavage sites, capable of yielding several smaller peptides, each displaying a unique function. Mature human CgA shares 63% aa sequence identity with mouse and rat CgA. CgA is expressed exclusively in the secretory dense core granules of most normal and neoplastic neuroendocrine cells. Increased levels of CgA have been detected inpatients with neuroendocrine tumors as well as non-neuroendocrine tumors, hence CgA is an important serological marker for tumor diagnosis and monitoring tumorprogression/regression. It has been demonstrated in mouse model that full-length CgA cont

Alpha-1-acid glycoprotein 2 is a secreted protein that belongs to the calycin superfamily; lipocalin family.It is expressed by the liver and secreted in plasma. It appears to function in modulating the activity of the immune system during the acute-phase reaction. It functions as transport protein in the blood stream. It binds various hydrophobic ligands in the interior of its beta-barrel domain. It also binds synthetic drugs and influences their distribution and availability.

Renin is a member of the aspartyl proteinase family produced largely in part by the juxtaglomerular cells in the kidney. Renin is produced as prorenin with 43 pro residues at the N-terminal of mature Renin. The inactive prorenin becomes activated proteolytically by trypsin, cathepsin B, or other proteinases. Renin also has a very high selectivity for substrates due to a long peptide recognition on either side of the peptide bond undergoing cleavage. An octapeptide substrate was the minimum length to be cleaved by Renin. Renin plays a crucial role in the regulation of blood pressure and salt balance through the cleavage of angiotensinogen,which is the only known physiological substrate of Renin. Renin releases the decapeptide angiotensin I, which in turn is further converted to vasoactive hormone angiotensin II by angiotensin converting enzyme (ACE).

Fibronectin (FN) is a glycoprotein component of the extracellular matrix of the extracellular matrix (ECM) with roles in embryogenesis, development, and wound healing. More recently, FN has emerged as player in platelet thrombus formation and diseases associated with thrombosis including vascular remodeling, atherosclerosis, and cardiac repair following a myocardial infarct. Each monomer of FN consists of three types of homologous repeating units, that is 12 type I repeats, two type II repeats and 15-17 type III repeats. The occurrence of multiple isoforms results from alternative mRNA splicing of the ED-A, ED-B and III-CS regions, and subsequent post-translational modification. As an ECM component and one of the primary cell adhesion molecules, Fibronectin can be a ligand for fibrin, heparin, chondroitin sulfate, collagen/gelatin, as well as many integrin receptors through which FN mediates the variety of cellular signaling pathways. The study of solid human tumors showed among the ea

Alpha-fetoprotein (AFP) is classified as a member of the albuminoid gene superfamily consisting of albumin; AFP; vitaminD (Gc) protein; and alpha-albumin. AFP is a glycoprotein of 591 amino acids and a carbohydrate moiety. AFP is a major plasma protein produced by the yolk sac and the liver during fetal development. It is thought to be the fetal form of serum albumin. AFP binds to copper; nickel; fatty acids and bilirubin and is found in monomeric; dimeric and trimeric forms. AFP is one of the several embryo-specific proteins and is adominant serum protein as early in human embryonic life as one month; when albumin and transferrin are present in relatively small amounts. It is first synthesized in the human by the yolk sac and liver (1-2 months) and subsequently predominantly in the liver. A small amount of AFP is produced by the GI tract of the human conceptus. It has been proved that AFP may reappear in the serum in elevated amounts in adult life in association with normal restorativ

There are more than 320 CD unique clusters and subclusters have been identified. Some of the CD molecules serve as receptors or ligands important to the cell through initiating a signal cascade which then alter the behavior of the cell. Some CD proteins do not take part in cell signal process but have other functions such as cell adhesion. Cluster of differentiation 63 (CD63) is a member of the CD family and the transmembrane 4 superfamily,also known as the tetraspanin family. CD63 is a cellular surface glycoprotein characterized by the presence of four bydrophobic domains. CD63 had functions in mediating signal transduction processes and then regulate variety of cellular processes such as cell proliferation, activation and motility. It has reported that CD63 protein associated with tumor progression and served as a blood platlet activation marker and the deficiency of this protein may be associated with Hermansky-Pudlak syndrome.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade components of the extracellular matrix (ECM) and play essential roles in various physiological processes such as morphogenesis, differentiation, angiogenesis and tissue remodeling, as well as pathological processes including inflammation, arthritis, cardiovascular diseases, pulmonary diseases and tumor invasion. Neutrophil collagenase, also known as Matrix metalloproteinase-8, MMP-8, and CLG1, is a member of the peptidase M10A family. MMP-8 may affect the metastatic behaviour of breast cancer cells through protection against lymph node metastasis, underlining the importance of anti-target identification in drug development. MMP-8 in the tumour may have a protective effect against lymph node metastasis. MMP-8 may affect the metastatic behaviour of breast cancer cells through protection against lymph node metastasis, underlining the importance of anti-target identification in drug dev

FcγRIIB is a low affinity receptor that recognizes the Fc portion of IgG. The human CD32 group consists of FcγRIIA, FcγRIIB, and FcγRIIC proteins that share 94-99% sequence identity in their extracellular domains but differ substantially in their transmembrane and cytoplasmic domains. FcγRII protein is expressed on cells of both myeloid and lymphoid lineages as well as on cells of non-hematopoietic origin. FcγRIIB has an intrinsic cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) and delivers an inhibitory signal upon ligand binding. Ligation of FcγRIIB on B cells down-regulates antibody production and in some circumstances may promote apoptosis. Co-ligation of FcγRIIB on dendritic cells inhibits maturation and blocks cell activation. FcγRIIB may also be a target for monoclonal antibody therapy for malignancies. FcγRIIB plays an important negative-regulating role through modulating the signals from activation receptors.