Home

Neurotrophin family

Neurotrophin family consists of a family of proteins that implicated in several different functions in the nervous system, including survival, proliferation, differentiation, myelination, apoptosis, axonal growth, and synaptic plasticity Neurotrophins belong to a family of polypeptide growth factors that control the apoptotic death or survival, growth, and differentiation of neurons. NTFs also regulate several other cell populations such as lymphoid, epithelial, oligoglia, and mast cells

Neurotrophin/Trk Family. The neurotrophin family is comprised of at least four proteins including NGF, BDNF, NT-3, and NT-4/5. These secreted cytokines are synthesized as prepropeptides that are proteolytically processed to generate active propeptides and mature protein homodimers. Mature NT-4 also forms heterodimers with BDNF or NT-3 The neurotrophin family of soluble growth factors comprises small polypeptides (12 to 13 kDa) that function as noncovalently associated homodimers. The tertiary structure of NGF reveals a tertiary fold and a cysteine knot. Neurotrophins are found in all mammals and lower vertebrates Neurotrophins are a family of proteins that induce the survival, development, and function of neurons. They belong to a class of growth factors, secreted proteins that can signal particular cells to survive, differentiate, or grow. Growth factors such as neurotrophins that promote the survival of neurons are known as neurotrophic factors A novel member of the neurotrophin family, zebrafish neurotrophin-7 (zNT-7), was isolated from the zebrafish Danio rerio. The amino acid sequence of zNT-7 is more closely related to that of fish nerve growth factor (NGF) and neurotrophin-6 (NT-6) than to that of any other neurotrophin. zNT-7 is, however, equally related to fish NGF and NT-6 (65. Neurotrophin family signaling Factors of the neurotrophin family (NGF, BDNF and neurotrophins NT-3 and NT-4/5), promote neuronal survival or death

Sigma-Aldrich Online Catalog Product List: Neurotrophin family - includes nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrohin-3 (NT-3) and neurotrohin-4 (NT-4 Background and ObjectivesInherited retinal degenerations (IRDs) are an untreatable cause of blindness due to photoreceptor apoptosis. Blocking apoptosis by exogenous neurotrophic factor administration is a promising therapeutic strategy in IRDs. The neurotrophin (NT) family are a group of peptide growth factors homologous to nerve growth factor that regulate the development, differentiation. Search this site. DNA@@@ 5' flanking regio

All Neurotrophins are a family of structurally related proteins known neurotrophin genes share a common organization: they required for the development and function of the vertebrate encode for a pre-pro-protein that is translocated to the endo- nervous system where they regulate survival, differentiation and plasmic reticulum and proteolitically processed to yield the synaptic plasticity of specific neuronal populations The neurotrophins are a family of proteins that are essential for the development of the vertebrate nervous system. Each neurotrophin can signal through two different types of cell surface receptor..

Neurotrophin family - Sino Biologica

Neurotrophins - an overview ScienceDirect Topic

Neurotrophin/Trk Family Research Areas: R&D System

NGF and the other known members of the neurotrophin family, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5) are conserved as distinct genes over large. The neurotrophin family of neurotrophic factors includes NGF, brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3) and NT-4. Each neurotrophin acts with high affinity on tropomyosin-receptor kinase (Trk) receptors, denoted TrkA for NGF, TrkB for BDNF and NT-4, and TrkC for NT-3 (4, 6, 44). Primary sensory nerves are also modulated by. NTF3 (neurotrophin 3) is a neurotrophic factor belonging to the NGF (nerve growth factor) family. This protein is made up of 257 amino acids, with a prepro region of 138 amino acids and the mature sequence of 119 residues

A novel member of the neurotrophin family, zebrafish neurotrophin-7 (zNT-7), was isolated from the zebrafish Danio rerio. The amino acid sequence of zNT-7 is more closely related to that of fish nerve growth factor (NGF) and neurotrophin-6 (NT-6) than to that of any other neurotrophin. zNT-7 is, however, equally related to fish NGF and NT-6 (65% and 63% amino acid sequence identity. discovered neurotrophin in mammals, and the least well understood, several aspects distinguish NT-4 from other members of the neurotrophin family. It is the most divergent member and, in contrast to the other neurotrophins, its expression is ubiquitous and appears to be less influenced by environmental signals

Neurotrophin - an overview ScienceDirect Topic

Neurotrophin Family Receptors There are two distinct types of neurotrophin receptors, tropomyosin kinase (Trk) receptors and neurotrophin receptor p75 (NGF R). Trophic actions that promote neuronal survival are dependent on mature neurotrophins binding to Trk receptors. In contrast, apoptosis is transduced b The recent molecular cloning of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) has established the existence of an NGF-related family of neurotrophic factors - the neurotrophins. Purification and recombinant production of BDNF and NT-3 has allowed the initiation or extension of in vitro studies of the neuronal specificity of. The trk family of neurotrophin receptors, trkA, trkB, and trkC, and their neurotrophin ligands, promote the survival, growth, and differentiation of central nervous system neurons and other neural crest-derived cells ().In cell culture, expression and stimulation of the trk family receptors can result in cell proliferation or differentiation, depending on the cell type The neurotrophin receptor tyrosine kinase (NTRK) family is made up of 3 genes crucial to nervous system development and physiology. These genes - NTRK1, NTRK2, and NTRK3 - encode the receptors TRKA, TRKB, and TRKC, respectively

Neurotrophin - Wikipedi

Barreiro, E. (2014). Trk Family Neurotrophin Receptors and p75 Receptor. A Multiple Competing Hypothesis Case in the Nerve Growth Factor (NGF) History. Advances in Historical Studies, 3, 93-103. doi: 10.4236/ahs.2014.32009 Neurotrophin PMG®. Neurotrophin PMG is a Protomorphogen™ extract formula that supports healthy central nervous system function.*. Provides a unique profile of minerals, nucleotides, and peptides*. Suggested Use: One tablet, three times per day on an empty stomach, or as directed. Caution: This product is processed in a facility that.

Neurotrophin-3, or NT-3, is a neurotrophic factor, in the NGF-family of neurotrophins.It is a protein growth factor which has activity on certain neurons of the peripheral and central nervous system; it helps to support the survival and differentiation of existing neurons, and encourages the growth and differentiation of new neurons and synapses. NT-3 was the third neurotrophic factor to be. The EMBO Journal Vol.17 No.9 pp.2534-2542, 1998 Early evolutionary origin of the neurotrophin receptor family Ronald E.van Kesteren1, Michael Fainzilber2,3, Garry Hauser4, Jan van Minnen, Erno Vreugdenhil5, August B.Smit, Carlos F.Iba´n˜ez2, Wijnand P.M.Geraerts an Neurotrophin family. Biological effects of all the members of this family are mediated through activation of 1 or more of the 3 members of the tropomyosin-related kinase (Trk) family of receptor tyrosine kinases, which leads to activation of Ras, phosphatidylinositol 3-kinase, phospholipase C-γ1, and signaling pathways controlled through these proteins, including the mitogen-activated protein.

Neurotrophin-7: a novel member of the neurotrophin family

  1. Congenital scoliosis is a condition characterized by spinal curvature beyond the physiological norm. The molecular mechanisms underlying the pathogenesis of congenital scoliosis are beginning to be clarified; however, the genes related to congenital scoliosis are still unknown. We herein report the results of a comprehensive analysis of gene expression in the spines from a rat model of.
  2. The neurotrophin family of neurotrophic factors are well-known for their effects on neuronal survival and growth. Over the past decade, considerable evidence has accumulated from both humans and animals that one neurotrophin, nerve growth factor (NGF), is a peripheral pain mediator, particularly in inflammatory pain states. NGF is upregulated in a wide variety of inflammatory conditions, and.
  3. title = Early evolutionary origin of the neurotrophin receptor family, abstract = Neurotrophins and their Trk receptors play a crucial role in the development and maintenance of the vertebrate nervous system, but to date no component of this signalling system has been found in invertebrates
  4. ant of neurotrophin responsiveness of sensory neurons. Although it has been apparent for some time that subpopulations of dorsal root and trige
  5. Neurotrophin-3 (NT-3) is a member of the NGF family of neurotrophic factors (also named neurotrophins) that are required for the differentiation and survival of specific neuronal subpopulations in both the central as well as the peripheral nervous systems. The neurotrophin family is comprised of at least four proteins including NGF, BDNF, NT-3.
  6. The protein encoded by this gene is a member of the neurotrophin family, that controls survival and differentiation of mammalian neurons. This protein is closely related to both nerve growth factor and brain-derived neurotrophic factor

Development - Neurotrophin family signaling Pathway Map

Neurotrophin and GDNF family ligands promote survival and alter excitotoxic vulnerability of neurons derived from murine embryonic stem cells Chul Sang Lee, Lee Y. Tee, Susan Dusenbery, Toshihiro Takata, Judith P. Golden , Brian A. Pierchala, David I. Gottlieb, Eugene M. Johnson, Dennis W. Choi, B. Joy Snide Neurotrophins signal via two types of receptors, the high-affinity trk receptor and the low-affinity p75 receptor . The high-affinity receptor for NGF is trkA; for BDNF and NT-4/5, it is trkB; for NT-3, it is trkC. The p75 receptor can be activated by all members of the neurotrophin family (2, 3) 1.1. Neurotrophins. Neurotrophins are small proteins vital for neuronal growth, differentiation, survival, and plasticity . Members of the mammalian neurotrophin family include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5) The neurotrophin family of neurotrophic factors can influence the neuronal cytoskeleton to regulate both axonal growth and guidance. The present review details some of the ways in which neurotrophins elicit these effects. Axonal elongation Basic mechanisms of axonal extension Axonal elongation depends on the dynamics and structure of actin.

Neurotrophin family - includes nerve growth factor (NGF

BDNF, also known as Brain-derived neurotrophic factor, is encoded by the BDNF Gene family in humans. This is a member of the growth factors that are the neurotrophin family and as such is related to nerve growth factor. This is a neurotrophic factor and, as the name suggests is found in the brain. Research which discovered this dates back to 1989 During nerve development, neurotrophins help nerve cells decide if they are going to live or die. Neurotrophins are small proteins secreted in the nervous system at extremely low concentrations. Low levels of a neurotrophin are needed to keep nerve cells alive. However, in some cases, presence of a neurotrophin can have the opposite effect, initiating cell-death

, respectively, and are the preferred receptors of the neurotrophin family of growth factors, which includes nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3. Neurotrophin and GDNF family ligand receptor expression in vagal sensory nerve subtypes innervating the adult guinea pig respiratory tract. American Journal of Physiology - Lung Cellular and Molecular Physiology , 300 (5), 790 - 798 The neurotrophin family of growth factors, comprised of nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4), is implicated in the physiology of chronic pain. Given the clinical efficacy of anti-NGF monoclonal antibody (mAb) therapies, there is significant interest in the.

Neurotrophin Family Members as Neuroprotectants in Retinal

  1. DURING vertebrate development, many neurons depend for survival and differentiation on their target cells 1-3 . The best documented mediator of such a retrograde trophic action is the neurotrophin nerve growth factor (NGF) 1 . NGF and the other known members of the neurotrophin family, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5) are conserved.
  2. Neurotrophins are a highly homologous family of secreted growth factors that have been extensively studied for their roles in the proliferation, survival, and differentiation of various cell populations in the mammalian nervous system. Each neurotrophin interacts with the p75 receptor and a specific member of the trk tyrosine kinase receptor.
  3. The low-affinity neurotrophin receptor p75 and the family of tyrosine kinases (trks) serve as receptors for target-derived neurotrophins. It has been shown that all neurotrophins of the NGF family bind with similar affinity to the p75 receptor molecule (Chao and Hempstead 1995).The trk receptors bind neurotrophins specifically with high affinity
  4. Neurotrophin-3. Short name: NT-3. Alternative name(s): HDNF. Nerve growth factor 2. Short name: Family and domain databases. Gene3D i: 2.10.90.10, 1 hit InterPro i: View protein in InterPro IPR029034, Cystine-knot_cytokine IPR020408, Nerve_growth_factor-like IPR002072, Nerve.
  5. Neurotrophins are a family of secreted proteins that act by binding to tropomyosin receptor kinase (Trk) or p75NTR receptors to regulate nervous system development and plasticity. Increasing evidence indicates that neurotrophins and their receptors in cancer cells play a role in tumor growth and resistance to treatment. In this review, we summarize evidence indicating that neurotrophin.

The Neurotrophin Family of Neurotrophic Factors: An

The neurotrophin family consists of nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), and neurotrophin 4 (NT-4). Neurotrophins exert their functions through engagement of Trk tyrosine kinase receptors or p75 neurotrophin receptor (p75NTR). Neurotrophin/Trk signaling is regulated by connecting a variety. BDNF is a member of the NGF family of neurotrophic growth factors. Like other members of this family, BDNF supports neuron proliferation and survival. BDNF can bind to a low affinity cell surface receptor called LNGFR, which also binds other neurotrophins such as NGF, NT-3 and NT-4 NTF4. 143. Annotation score: Annotation score:1 out of 5. The annotation score provides a heuristic measure of the annotation content of a UniProtKB entry or proteome. This score cannot be used as a measure of the accuracy of the annotation as we cannot define the 'correct annotation' for any given protein Scientific background . Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors which includes nerve growth factor (NGF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5).. All neurotrophins are synthesized as preproneurotrophin precursors that are subsequently processed within the intracellular transport pathway to yield proneurotrophins that are. Neurotrophin and GDNF family ligand receptor expression in vagal sensory nerve subtypes innervating the adult guinea pig respiratory tract TinaMarie Lieu,1 Marian Kollarik,1,2 Allen C. Myers,1 and Bradley J. Undem1 1The Johns Hopkins University Medical Institutions, Baltimore, Maryland and 2Jessenius Medical School, Comenius University, Martin, Slovaki

Accumulated evidence suggests the role of neurotrophins in the neuronal develop- ment, network maintenance, plasticity and possible dysregulation in AD-like pathologies. The neurotrophin family member nerve growth factor (NGF) deprivation resulted in The cytoplasmic domain of the p75 neurotrophin receptor (p75 NTR, also known as NGFR and TNFRSF16) contains a C-terminal DD connected to the transmembrane (TM) domain by a 60-residue-long linker region (Liepinsh, 1997). p75 NTR is a receptor for members of the neurotrophin family, such as nerve growth factor (NGF) and brain-derived neurotrophic. These neurotrophins bind two groups of receptors. The p75 NTR receptor is common to all four neurotrophins and is a member of the tumor necrosis factor receptor family. The tropomyosin-related kinase (Trk) receptors are receptor tyrosine kinases (RTKs) and three receptors form this family: TrkA, TrkB, and TrkC 1 CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Neurotrophin-4 (NT-4) is perhaps the still most enigmatic member of the neurotrophin family. We show here that NT-4 is expressed in neurons of paravertebral and prevertebral sympathetic ganglia, i.e., the superior cervical (SCG), stellate (SG), and celiac (CG) ganglion Neurotrophins are small proteins vital for neuronal growth, differentiation, survival, and plasticity. Members of the mammalian neurotrophin family include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin- 4/5 (NT-4/5). Their neurotrophic effects are mediated by the tropomyosin receptor kinase (Trk) receptors, membrane-bound receptor.

Neurotrophin Family - dnareplicationsyste

Neurotrophins are structurally related proteins regulating brain development and function. Molecular evolution studies of neurotrophins and their receptors are essential for understanding the mechanisms underlying the coevolution processes of these gene families and how they correlate with the increased complexity of the vertebrate nervous system Neurotrophins (nerve growth factors (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5)) are a family of secreted growth factors that regulate survival, growth, differentiation, and maintenance of neurons in both the central nervous system (CNS) and the peripheral nervous system (PNS). The binding of neurotrophins to their cognate receptors. The trk family of neurotrophin receptors, trkA, trkB, and trkC, and their neurotrophin ligands, promote the survival, growth, and differentiation of central nervous system neurons and other neural crest-derived cells (1). In cell culture, expression and stimulation of the trk family receptors can result in cell prolifer P.1.a.007 Neurotrophin family genes (BDNF and NTRK2) and personality traits in healthy individuals Tools RDF+XML BibTeX RDF+N-Triples JSON RefWorks Dublin Core Simple Metadata Refer METS HTML Citation ASCII Citation OpenURL ContextObject EndNote MODS OpenURL ContextObject in Span MPEG-21 DIDL EP3 XML Reference Manager RDF+N3 Multiline CS

It is beyond doubt that the neurotrophin family of proteins plays key roles in determining the fate of the neuron, not only during embryonic development, but also in the adult brain. Neurotrophins such as NGF (nerve growth factor) and BDNF (brain-derived neurotrophic factor) can play dual roles: first, in neuronal survival and death, and, secondly, in activity-dependent plasticity. The. Correlation of the expression of neurotrophins family and its receptors with cell proliferation and invasion in ovarian cancer Liang Li; Affiliations Liang Li Department of Obstetrics and Gynecology, Guangyuan First People's Hospital in Sichuan Province, Guangyuan, Sichuan Province, 628017.

Slitrks as emerging candidate genes involved in

The common neurotrophin receptor, p75NTR, has been shown to signal in the absence of Trk tyrosine kinase receptors, including induction of neural apoptosis and activation of NF-κB. However, the mechanisms by which p75NTR initiates these intracellular signal transduction pathways are unknown. Here we report interactions between p75NTR and the six members of TRAF (tumor necrosis factor receptor. Download PDF: Sorry, we are unable to provide the full text but you may find it at the following location(s): http://hdl.handle.net/11380/59... (external link The neurotrophin receptor p75 NTR is now known to have more diverse functions than that of being a helper for the Trk receptors.We show that the brain-derived neurotrophic factor (BDNF) acts through p75 NTR to enhance myelin formation. The neurotrophins, a family of growth factors including nerve growth factor (NGF), BDNF, neurotrophin-3 (NT3), and neurotrophin-4/5 (NT4/5), exert their.

(PDF) Molecular evolution of the neurotrophin family

Recruitment (prior to visit 1) the participant information sheet and consent form (PISCF) will be given to take home, read, and discuss with their family, friends and health care professional. At visit 1, the research team will go through the entire form to explain the benefits and risks, and answer any questions you or your family may have This protein tyrosine kinase family is the neurotrophin receptors set. The discovery that in cells expressing Trk receptors, neurotrophins promote cell survival changed everything previously knew about NGF. Indeed, by 1990, NGF had been known about for almost 40 years and it was thought that all have already been said about it

The appearance of a neurotrophin due to biosynthesis or secretion by cells in a neuron's target field, resulting in an increase in its intracellular or extracellular levels. A neurotrophin is any of a family of growth factors that prevent apoptosis in neurons and promote nerve growth What does neurotrophin mean? Information and translations of neurotrophin in the most comprehensive dictionary definitions resource on the web. Login . Neurotrophin. Neurotrophins are a family of proteins that induce the survival, development, and function of neurons. They belong to a class of growth factors, secreted proteins that are. The Trk family of neurotrophin receptors plays essential roles in cell fate specification, survival, growth, and differentiation. Their expression patterns are complex and dynamically regulated under many physiological and pathological conditions. However, the molecular mechanisms that control their tissue-specific expression are largely unknown

Neurotrophins regulate development, maintenance, and function of vertebrate nervous systems. Neurotrophins activate two different classes of receptors, the Trk family of receptor tyrosine kinases and p75NTR, a member of the TNF receptor superfamily. Through these, neurotrophins activate many signaling pathways, including those mediated by ras and members of the cdc-42/ras/rho G protein. Neurotrophins also show weak affinity towards the p75 neurotrophin receptor owing to structural similarities with the Trk family receptors . Interestingly, mediates the cell-death-promoting tumor necrosis factor (TNF) receptor superfamily, which includes factors such as FasL, TNF receptor (TNFR)-I, TNFR-II, CD40, OX40, and TNF p75 NTR is a transmembrane glycoprotein and a member of the tumor necrosis factor (TNF) superfamily that was originally isolated as a nerve growth factor (NGF) receptor, but has since been shown to bind both the mature and precursor forms of the neurotrophin family of ligands (brain-derived neurotrophin factor [BDNF], neurotrophin-3 [NT-3], and. A cochlear implant may be used to electrically stimulate spiral ganglion neurons (SGNs) in people with severe sensorineural hearing loss (SNHL). However, these neurons progressively degenerate after SNHL due to loss of neurotrophins normally supplied by sensory hair cells (HCs). Experimentally, exogenous neurotrophin administration prevents SGN degeneration but can also result in abnormal.

understood. The model for TrkB activation by neurotrophin ligands, including BDNF, has been proposed. The binding of BDNF homodimers to the ectodomain of TrkB induces recep Neurotrophin is listed in the World's largest and most authoritative dictionary database of abbreviations and acronyms. Neurotrophin - What does Neurotrophin stand for? BDNF, GDNF, and NGF belong to the neurotrophin family, which has an important role in neuronal survival and/or protection and axonal growth [22] We now report that changes in irk family neurotrophin receptor expression appear to be involved in both preneoplastic thyroid C cell hyperplasia and later tumor progression. Only a subset of normal C cells expresses trk family receptors, but, in C cell hyperplasia, the affected cells consistently express trkB, with variable expression of trkA.

Figure 1 from Targeting TRK family proteins in cancer

Neurotrophins and their receptors: A convergence point for

Brain-Derived Neurotrophic Factor; BDNFFrontiers | Regulation of neurotrophin receptor (Trk

Trk receptor - Wikipedi

  1. Rejji Kuruvilla is a professor of biology whose research focuses on the development and functions of the sympathetic nervous system. She received her BS from Calcutta University in India, her PhD from the University of Houston, and did her postdoctoral work at Johns Hopkins University School of Medicine
  2. QUESTION 34 Neurotrophins bind to a family of receptor tyrosine kinases called Tiks. Each traphic factor binds to a specific receptor and is required for the survival of distra popular titrarona Use the following information as TAUE: the Trka protein is expressed in nociceptive neurons the Traprotuin is expressed in mechanoreceptors; the TC biotein hered in proprio What can of neurons would be.
  3. The neurotrophins promote neuronal survival and differentiation through binding to the Trks, a family of tyrosine kinase receptors, and induce apoptosis through a 75kD receptor, p75. While significant progress has been made in elucidating the mechanisms by which the Trks promote survival, much less is known about how p75 induces cell death

Sortilin is a member of the VPS10P domain receptor gene family, a class of sorting and signalling receptors in neurons. This gene family also includes SORLA/LR11, the neuronal sorting factor for APP. Sortilin has been shown to constitute an essential component of the receptor complex that transmits pro-neurotrophin-dependent death signals in. Furthermore, we found that different AD drugs directly bind to a site formed by a dimer of TRKB TMDs, thereby facilitating cell surface expression of TRKB and promoting BDNF signaling. These data suggest that direct binding to TRKB and promotion of BDNF-mediated plasticity is a mechanism of action for AD drugs Study Description. Neurotrophins (NTs) constitute a family of growth factors, which regulated differentiation, proliferation, and survival of both neuronal cells and astrocytes. In recent years, several studies have provided evidences that the cellular effects of NGF Nerve Growth Factor , BDNF Brain-Derived Neurotrophic Factor and NT-3. The trk family of receptors mediates nerve growth factor and neurotrophin-3 effects in melanocytes. M Yaar, M S Eller, P DiBenedetto, W R Reenstra, S Zhai, T McQuaid, M Archambault, and B A Gilchrest Department of Dermatology, Boston University School of Medicine, Massachusetts 02118..

The Neurotrophic tyrosine kinase (NTRK) Gene Famil