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Gdnf
Glial cell line-derived neurotrophic factor (GDNF) is a protein that, in humans, is encoded by the ''GDNF'' gene. GDNF is a small protein that potently promotes the survival of many types of neurons. It signals through GFRα receptors, particularly GFRα1. It is also responsible for the determination of spermatogonia into primary spermatocytes, i.e. it is received by RET proto-oncogene (RET) and by forming gradient with SCF it divides the spermatogonia into two cells. As the result there is retention of spermatogonia and formation of spermatocyte. GDNF family of ligands (GFL) GDNF was discovered in 1991, and is the first member of the GDNF family of ligands (GFL) found. Function GDNF is highly distributed throughout both the peripheral and central nervous system. It can be secreted by astrocytes, oligodendrocytes, Schwann cells, motor neurons, and skeletal muscle during the development and growth of neurons and other peripheral cells. The GDNF gene encodes a highly conserved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GFRα1
GDNF family receptor alpha-1 (GFRα1), also known as the GDNF receptor, is a protein that in humans is encoded by the ''GFRA1'' gene. Function Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) are two structurally related, potent neurotrophic factors that play key roles in the control of neuron survival and differentiation. The protein encoded by this gene is a member of the GDNF receptor family. It is a glycosylphosphatidylinositol(GPI)-linked cell surface receptor for both GDNF and NTN, and mediates activation of the RET tyrosine kinase receptor. This gene is a candidate gene for Hirschsprung disease. Two alternatively spliced transcript variants encoding different isoforms have been described for this gene. Interactions GDNF family receptor alpha 1 has been shown to interact with GDNF and RET proto-oncogene. See also * GFRα The GDNF family receptor-α (GFRα) proteins are a group of co-receptors which form complexes with GDNF-family ligands (G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GDNF Family Of Ligands
The GDNF family of ligands (GFL) consists of four neurotrophic factors: glial cell line-derived neurotrophic factor (GDNF), neurturin (NRTN), artemin (ARTN), and persephin (PSPN). GFLs have been shown to play a role in a number of biological processes including cell survival, neurite outgrowth, cell differentiation and cell migration. In particular signalling by GDNF promotes the survival of dopaminergic neurons. Signalling complex formation At the cell surface of target cells, a signalling complex forms, composed of a particular GFL dimer, a receptor tyrosine kinase molecule RET, and a cell surface-bound co-receptor that is a member of the GFRα protein family. The primary ligands for the co-receptors GFRα1, GFRα2, GFRα3, and GFRα4 are GDNF, NRTN, ARTN, and PSPN, respectively. Upon initial GFL-GFRα complex formation, the complex then brings together two molecules of RET, triggering trans-autophosphorylation of specific tyrosine residues within the tyrosine kinase domain o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotrophic Factor
Neurotrophic factors (NTFs) are a family of biomolecules – nearly all of which are peptides or small proteins – that support the growth, survival, and cell differentiation, differentiation of both developing and mature neurons. Most NTFs exert their trophic effects on neurons by signaling through tyrosine kinases, usually a receptor tyrosine kinase. In the mature nervous system, they promote neuronal survival, induce synaptic plasticity, and modulate the formation of long-term memories. Neurotrophic factors also promote the initial growth and development of neurons in the central nervous system and peripheral nervous system, and they are capable of regrowing damaged neurons in test tubes and animal models. Some neurotrophic factors are also released by the target tissue in order to axon guidance, guide the growth of developing axons. Most neurotrophic factors belong to one of three families: (1) neurotrophins, (2) glial cell-line derived neurotrophic factor family liga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RET Proto-oncogene
The ''RET'' proto-oncogene encodes a receptor tyrosine kinase for members of the glial cell line-derived neurotrophic factor (GDNF) family of extracellular signalling molecules. ''RET'' loss of function mutations are associated with the development of Hirschsprung's disease, while gain of function mutations are associated with the development of various types of human cancer, including medullary thyroid carcinoma, multiple endocrine neoplasias type 2A and 2B, pheochromocytoma and parathyroid hyperplasia. Structure ''RET'' is an abbreviation for "rearranged during transfection", as the DNA sequence of this gene was originally found to be rearranged within a 3T3 fibroblast cell line following its transfection with DNA taken from human lymphoma cells. The human gene ''RET'' is localized to chromosome 10 (10q11.2) and contains 21 exons. The natural alternative splicing of the ''RET'' gene results in the production of 3 different isoforms of the protein RET. RET51, RET43 and RET9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receptor Tyrosine Kinases
Receptor tyrosine kinases (RTKs) are the high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. Of the 90 unique tyrosine kinase genes identified in the human genome, 58 encode receptor tyrosine kinase proteins. Receptor tyrosine kinases have been shown not only to be key regulators of normal cellular processes but also to have a critical role in the development and progression of many types of cancer. Mutations in receptor tyrosine kinases lead to activation of a series of signalling cascades which have numerous effects on protein expression. Receptor tyrosine kinases are part of the larger family of protein tyrosine kinases, encompassing the receptor tyrosine kinase proteins which contain a transmembrane domain, as well as the non-receptor tyrosine kinases which do not possess transmembrane domains. History The first RTKs to be discovered were EGF and NGF in the 1960s, but the classification of receptor tyrosine kinases was not d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GFRα
The GDNF family receptor-α (GFRα) proteins are a group of co-receptors which form complexes with GDNF-family ligands (GFLs) to activate RET, the receptor of the GFLs. The GFRα co-receptors include the following: * GFRα1 – preference for GDNF * GFRα2 – preference for neurturin * GFRα3 – preference for artemin * GFRα4 – preference for persephin * GFRAL - receptor for GDF15 Growth/differentiation factor 15 (GDF15) was first identified as Macrophage inhibitory cytokine-1 or MIC-1. It is a protein belonging to the transforming growth factor beta superfamily. Under normal conditions, GDF-15 is expressed in low concent ... References {{DEFAULTSORT:GFRa TGFβ domain Proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligodendrocytes
Oligodendrocytes (), or oligodendroglia, are a type of neuroglia whose main functions are to provide support and insulation to axons in the central nervous system of jawed vertebrates, equivalent to the function performed by Schwann cells in the peripheral nervous system. Oligodendrocytes do this by creating the myelin sheath. A single oligodendrocyte can extend its processes to 50 axons, wrapping approximately 1 μm of myelin sheath around each axon; Schwann cells, on the other hand, can wrap around only one axon. Each oligodendrocyte forms one segment of myelin for several adjacent axons. Oligodendrocytes are found only in the central nervous system, which comprises the brain and spinal cord. These cells were originally thought to have been produced in the ventral neural tube; however, research now shows oligodendrocytes originate from the ventral ventricular zone of the embryonic spinal cord and possibly have some concentrations in the forebrain. They are the last cell t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parkinson's Disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms become more common. The most obvious early symptoms are tremor, rigidity, slowness of movement, and difficulty with walking. Cognitive and behavioral problems may also occur with depression, anxiety, and apathy occurring in many people with PD. Parkinson's disease dementia becomes common in the advanced stages of the disease. Those with Parkinson's can also have problems with their sleep and sensory systems. The motor symptoms of the disease result from the death of cells in the substantia nigra, a region of the midbrain, leading to a dopamine deficit. The cause of this cell death is poorly understood, but involves the build-up of misfolded proteins into Lewy bodies in the neurons. Collectively, the main motor symptoms are also known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirschprung's Disease
Hirschsprung's disease (HD or HSCR) is a birth defect in which nerves are missing from parts of the intestine. The most prominent symptom is constipation. Other symptoms may include vomiting, abdominal pain, diarrhea and failure to thrive, slow growth. Symptoms usually become apparent in the first two months of life. Complications may include enterocolitis, megacolon, bowel obstruction and intestinal perforation. The disorder may occur by itself or in association with other genetic disorders such as Down syndrome or Waardenburg syndrome. About half of isolated cases are linked to a specific genetic mutation, and about 20% occur within families. Some of these occur in an autosomal dominant manner. The cause of the remaining cases is unclear. If otherwise normal parents have one child with the condition, the next child has a 4% risk of being affected. The condition is divided into two main types, short-segment and long-segment, depending on how much of the bowel is affected. Rarely, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furin
Furin is a protease, a proteolytic enzyme that in humans and other animals is encoded by the ''FURIN'' gene. Some proteins are inactive when they are first synthesized, and must have sections removed in order to become active. Furin cleaves these sections and activates the proteins. It was named furin because it was in the upstream region of an oncogene known as FES. The gene was known as FUR (FES Upstream Region) and therefore the protein was named furin. Furin is also known as PACE (Paired basic Amino acid Cleaving Enzyme). A member of family S8, furin is a subtilisin-like peptidase. Function The protein encoded by this gene is an enzyme that belongs to the subtilisin-like proprotein convertase family. The members of this family are proprotein convertases that process latent precursor proteins into their biologically active products. This encoded protein is a calcium-dependent serine endoprotease that can efficiently cleave precursor proteins at their paired basic amino acid pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorneuron
A motor neuron (or motoneuron or efferent neuron) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly control effector organs, mainly muscles and glands. There are two types of motor neuron – upper motor neurons and lower motor neurons. Axons from upper motor neurons synapse onto interneurons in the spinal cord and occasionally directly onto lower motor neurons. The axons from the lower motor neurons are efferent nerve fibers that carry signals from the spinal cord to the effectors. Types of lower motor neurons are alpha motor neurons, beta motor neurons, and gamma motor neurons. A single motor neuron may innervate many muscle fibres and a muscle fibre can undergo many action potentials in the time taken for a single muscle twitch. Innervation takes place at a neuromuscular junction and twitches can become superimposed as a result of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
