Posts Tagged ‘Clusters of differentiation’

What is VPREB1

Friday, December 12th, 2008

Pre-B lymphocyte gene 1, also known as VPREB1, is a human gene.[1] VPREB1 has also recently been designated CD179A (cluster of differentiation 179A).

CD179a (VpreB) is a 126 aa-long polypeptide with apparent MW of 16-18 kDa. It is expressed selectively at the early stages of B cell development, namely, in proB and early preB cells. CD179a has an Ig V domain-like structure, but lacks the last beta-strand (beta7) of a typical V domain. Instead, it has a carboxyl terminal end that shows no sequence homologies to any other proteins. CD179a associates non-covalently with CD179b (lambda5 or lambda-like) carrying an Ig C domain-like structure to form an Ig light chain-like structure, which is called the surrogate light chain or pseudo light chain. In this complex, the incomplete V domain of CD179a appears to be complemented by the extra beta7 strand of CD179b. On the surface of early preB cells, CD179a/CD179b surrogate light chain is disulfide-linked to membrane-bound Ig mu heavy chain in association with a signal transducer CD79a/CD79b heterodimer to form a B cell receptor-like structure, so-called preB cell receptor (preBCR). Though no CD179a-related human disease or pathology has been reported yet, the deficiency of other components of preB cell receptor such as CD179b, Ig mu heavy chain and CD79a has been shown to result in severe impairment of B cell development and agammaglobulinemia in human. PreBCR transduces signals for: 1) cellular proliferation, differentiation from the proB cell to preB cell stage, 2) allelic exclusion at the Ig heavy chain gene locus, and 3) promotion of Ig light chain gene rearrangements. Thus, preBCR functions as a checkpoint in early B cell development to monitor the production of Ig mu heavy chain through a functional rearrangement of Ig heavy chain gene as well as the potency of Ig mu heavy chain to associate with Ig light chain.[1]

What is VE cadherin

Friday, December 12th, 2008

Cadherin 5, type 2 or VE-cadherin (vascular endothelial) also known as CD144 (Cluster of Differentiation 144), is a type of cadherin. It is encoded by the human gene CDH5.

It is a classical cadherin from the cadherin superfamily and the gene is located in a six-cadherin cluster in a region on the long arm of chromosome 16 that is involved in loss of heterozygosity events in breast and prostate cancer. The encoded protein is a calcium-dependent cell-cell adhesion glycoprotein comprised of five extracellular cadherin repeats, a transmembrane region and a highly conserved cytoplasmic tail. Functioning as a classic cadherin by imparting to cells the ability to adhere in a homophilic manner, the protein may play an important role in endothelial cell biology through control of the cohesion and organization of the intercellular junctions.[1]

Physiological significance of Urokinase receptor

Friday, December 12th, 2008

uPAR is a part of the plasminogen activation system, which in the healthy body is involved in tissue reorganization events such as mammary gland involution and wound healing. In order to be able to reorganize tissue it is important, that the old tissue can be degraded. An important mechanism in this degradation is the proteolysis cascade initiated by the plasminogen activation system. uPAR binds urokinase and thus restricts plasminogen activation to the immediate vicinity of the cell membrane. Thus uPAR seems to be an important player in the regulation of this process.

However the components of the plasminogen activation system have been found to be highly expressed in many malignant tumors, indicating that tumors are able to hijack the system, and use it in metastasis. Thus inhibitors of the various components of the plasminogen activation system has been sought as possible anticancer drugs.

uPAR has been involved in various other non-proteolytical processes related to cancer, such as cell migration, cell cycle regulation and cell adhesion.

Molecular characteristics of Urokinase receptor

Friday, December 12th, 2008

uPAR consists of three different domains of the Ly-6/uPAR/alpha-neurotoxin family. All three domains are necessary for high affinity binding of the primary ligand, urokinase. It has been possible to express uPAR recombinantly in CHO-cells and S2 cells from Drosophila melanogaster. 4 out of 5 of the possible glycosylation sites are used in vivo giving the protein a molecular weight of 50-60 kDA. Recently the structure of uPAR was solved by X-ray crystallography in complex with an peptide antagonist[1] and with its native ligand, urokinase[2].

Besides the primary ligand urokinase, uPAR interacts with several other proteins, among others: vitronectin, the uPAR associated protein (uPARAP) and the integrin family of membrane proteins.

What is Urokinase receptor

Friday, December 12th, 2008

The Urokinase receptor, also known as uPA receptor or uPAR or CD87 (Cluster of Differentiation 87), is multidomain glycoprotein tethered to the cell membrane with a glycosylphosphotidylinositol (GPI) anchor. uPAR was originally identified as a saturable binding site for urokinase on the cell surface.

What is Tumor associated calcium signal transducer 1

Friday, December 12th, 2008

Tumor-associated calcium signal transducer 1, also known as TACSTD1, is a human gene.[1] TACSTD1 has also been designated as CD326 (cluster of differentiation 326).

This 9-exon gene encodes a carcinoma-associated antigen and is a member of a family that includes at least two type I membrane proteins. This antigen is expressed on most normal epithelial cells and gastrointestinal carcinomas and functions as a homotypic calcium-independent cell adhesion molecule. The antigen is being used as a target for immunotherapy treatment of human carcinomas.[

What is TRAIL

Friday, December 12th, 2008

TNF-related apoptosis-inducing ligand (TRAIL), in the field of cell biology, is a ligand molecule which induces the process of cell death called apoptosis. It is a type II transmembrane protein with homology to other members of the tumor necrosis factor family.

In humans, the gene that encodes for TRAIL is located at chromosome 3q26.

TRAIL binds to the death receptors, DR4 and DR5. The process of apoptosis is caspase-8-dependent.

TRAIL has also been designated CD253 (cluster of differentiation 253).

What is TNFSF14

Friday, December 12th, 2008

Tumor necrosis factor (ligand) superfamily, member 14, also known as TNFSF14, is a human gene.[1] TNFSF14 has also been designated as CD258 (cluster of differentiation 258).

The protein encoded by this gene is a member of the tumor necrosis factor (TNF) ligand family. This protein is a ligand for TNFRSF14, which is a member of the tumor necrosis factor receptor superfamily, and which is also known as a herpesvirus entry mediator (HVEM). This protein may function as a costimulatory factor for the activation of lymphoid cells and as a deterrent to infection by herpesvirus. This protein has been shown to stimulate the proliferation of T cells, and trigger apoptosis of various tumor cells. This protein is also reported to prevent tumor necrosis factor alpha mediated apoptosis in primary hepatocyte. Two alternatively spliced transcript variant encoding distinct isoforms have been reported.[1]

What is TNFSF13

Friday, December 12th, 2008

Tumor necrosis factor (ligand) superfamily, member 13, also known as TNFSF13, is a human gene.[1] TNFSF13 has also been designated CD256 (cluster of differentiation 256).

The protein encoded by this gene is a member of the tumor necrosis factor (TNF) ligand family. This protein is a ligand for TNFRSF17/BCMA, a member of the TNF receptor family. This protein and its receptor are both found to be important for B cell development. In vitro experiments suggested that this protein may be able to induce apoptosis through its interaction with other TNF receptor family proteins such as TNFRSF6/FAS and TNFRSF14/HVEM. Three alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported.[1]

What is TNFRSF1A

Friday, December 12th, 2008

Tumor necrosis factor receptor superfamily, member 1A, also known as TNFRSF1A or CD120A, is a human gene. The protein encoded by this gene is a member of the Tumor necrosis factor receptor superfamily, which also contains TNFRSF1B. This protein is one of the major receptors for the tumor necrosis factor-alpha. This receptor can activate the transcription factor NF-kB, mediate apoptosis, and function as a regulator of inflammation. Antiapoptotic protein BCL2-associated athanogene 4 (BAG4/SODD) and adaptor proteins TRADD and TRAF2 have been shown to interact with this receptor, and thus play regulatory roles in the signal transduction mediated by the receptor. Germline mutations of the extracellular domains of this receptor were found to be associated with the human genetic disorder called periodic fever syndrome. Impaired receptor clearance is thought to be a mechanism of the disease.[1]