Neural Stem Cells
- CD133
The CD133 (also named AC133) antigen is a 97 kDa glycoprotein, with 5 transmembrane domains, that shows up as a 120 kDa band on protein gels due to glycosylation. It is a cell surface marker expressed by immature hematopoietic stem cells but not mature blood cells. In addition to hematopoietic stem and progenitor cells, CD133 has been found to be a marker for other stem and progenitor cells including neural and embryonic stem cells. It has been shown to be expressed in cancers, including some leukemias and brain tumours, that may be derived from stem cells. Low level expression has also been detected in the kidney, pancreas, placenta, and fetal liver.
- Fibronectine
Fibronectin is a glycoprotein present in a soluble dimeric form in plasma, and in a dimeric or multimeric form at the cell surface and in extracellular matrix. Fibronectin is involved in cell adhesion and migration processes including embryogenesis, wound healing, blood coagulation, host defense, and metastasis. They occur as dimers of two 200 kDa subunits. They have binding domains for bacterial proteins, collagens, heparin-like molecules and fibrin. Cellular fibronectin is widely distributed in the stroma of malignant tumours.
- GLUT
Glucose transporters are integral membrane glycoproteins involved in transporting glucose into most cells. Seven types of glucose transport carrier proteins, designated as Glut 1 to 7, facilitate glucose transport across the cell membrane. Molecular cloning of glucose transporters have identified a family of closely related genes that encode at least 7 proteins exhibiting high degree of amino acid homology (45% to 65%), all in the molecular weight range of 40 to 60 kDa. Individual members of the Glut family have predicted secondary structure characteristic of 12 membrane spanning domains of other transport carriers. The majority of differences in sequence homology in Glut proteins occur at 4 hydrophilic domains that may play a role in distinct tissue specific pattern of expression and targeting. All Glut proteins are glycosylated at or near the C terminus and are present on either cell surface or in intracellular sites. Some transporters exhibit dynamic trafficking between intracellular storage sites and plasma membranes in response to various stimuli. In some tissues Glut proteins are asymmetrically distributed between apical and basolateral membranes as in blood brain barrier and blood testis barriers.
GLUT1 is a major glucose transporter at the mammalian blood brain barrier. It is ubiquitous, and is present at high levels in primate erythrocytes and brain endothelial cells.
- Islet-1
Islet 1 is encoded by ISL1. Islet 1 is a transcription factor containing two amino-terminal LIM domains and one carboxy-terminal homeodomain. Islet 1 and ISL1 play an important role in the embryogenesis of pancreatic islets of Langerhans. In addition, mouse embryos made deficient in ISL1 fail to undergo neural tube motor neuron differentiation
- Musashi 1
In mammals, the Musashi family is important for cell fate determination, playing roles in maintenance of the stem-cell state, differentiation and tumorigenesis. Musashi1 (also known as Msi1), is selectivley expressed in neural progenitor cells, including neural stem cells. Outside the nervous system, Musashi1 is a selective marker for intestinal stem or early lineage cells. Musashi1 interacts with the Notch pathway during asymmetric cell division by binding teh 3' UTR of Numb. Numb is prevented from repressing Notch signaling when Musashi1 is present.
- Nestin
Nestin is a Class VI intermediate filament expressed in the developing central nervous system (CNS) in early embryonic neuroepithelial stem cells. This protein has been widely used as a predominant marker for stem / progenitor cells, glioma cells, and tumor endothelial cells in the mammalian CNS. Furthermore, it is a superior angiogenic marker to evaluate neovascularity of endothelial cells in tumor.
- P75 NGF
Nerve growth factor (NGF) is a polypeptide involved in the regulation of growth and differentiation of sympathetic and some sensory neurons, and is composed by 3 types of subunits (alpha, beta and gamma) that specifically interact to form a 7S, 130 kDa molecular weight complex. The beta-NGF subunit is a secreted protein that forms a homodimer before being incorporated into the NGF complex. The human and mouse sequences are very similar and mutations in this gene have been associated with hereditary sensory and autonomic neuropathy, type 5 (HSAN5). Deregulation of its expression has been associated with allergic rhinitis.
- PAX3
This protein is a member of the paired box (PAX) family of transcription factors. Members of the PAX family typically contain a paired box domain and a paired-type homeodomain. These proteins play critical roles during fetal development. Mutations in paired box gene 3 are associated with Waardenburg syndrome, craniofacial-deafness-hand syndrome, and alveolar rhabdomyosarcoma. The translocation t(2;13)(q35;q14), which represents a fusion between PAX3 and the forkhead gene, is a frequent finding in alveolar rhabdomyosarcoma. Alternative splicing results in transcripts encoding isoforms with different C-termini.
- Vimentin
Vimentin is the major subunit protein of the intermediate filaments of mesenchymal cells. It is believed to be involved with the intracellular transport of proteins between the nucleus and plasma membrane. Vimentin has been implicated to be involved in the rate of steroid synthesis via its role as a storage network for steroidogenic cholesterol containing lipid droplets. Vimentin phosphorylation by a protein kinase causes the breakdown of intermediate filaments and activation of an ATP and myosin light chain dependent contractile event. This results in cytoskeletal changes that facilitate the interaction of the lipid droplets within mitochondria, and subsequent transport of cholesterol to the organelles leading to an increase in steroid synthesis. Immunohistochemical staining for Vimentin is characteristic of sarcomas (of neural, muscle and fibroblast origin) compared to carcinomas which are generally negative. Melanomas, lymphomas and vascular tumors may all stain for Vimentin. Vimentin antibodies are thus of value in the differential diagnosis of undifferentiated neoplasms and malignant tumors. They are generally used with a panel of other antibodies including those recognising cytokeratins, lymphoid markers, S100, desmin and neurofilaments.