Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neural cell adhesion molecule (NCAM) belongs to the immunoglobulin (Ig) superfamily and is composed extracellularly of five Ig-like and two fibronectin type III (F3) modules. It plays a pivotal role in neuronal development and synaptic plasticity. NCAM signals via a direct interaction with the fibroblast growth factor receptor (FGFR). A 15-amino-acid long peptide, the FG loop (FGL) peptide, that is derived from the second F3 module of NCAM has been found to activate FGFR1. We here report that the FGL peptide, when administered intranasally to newborn rats, accelerated early postnatal development of coordination skills. In adult animals s.c. administration of FGL resulted in a prolonged retention of social memory. We found that FGL rapidly penetrated into the blood and cerebrospinal fluid after both intranasal and s.c. administration and remained detectable in the fluids for up to 5 hours.
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PMID:A neural cell adhesion molecule-derived fibroblast growth factor receptor agonist, the FGL-peptide, promotes early postnatal sensorimotor development and enhances social memory retention. 1678 19

Progression from C-cell hyperplasia (CCH) to medullary thyroid carcinoma (MTC) has been demonstrated to date only in familial forms, whereas in nonfamilial MTC, such hypothesis is suggested by the rare concurrence of both lesions, although no epidemiological and molecular data are available to prove or disprove this event. Therefore, the clinical management of patients with sporadic CCH is controversial. To evaluate the malignant potential of sporadic CCHs, pure laser-microdissected C-cell populations of 24 CCH cases, either reactive or associated with nonfamilial MTC, were analyzed for MTC-associated protein neural cell adhesion molecule expression and RET point mutations in exons 10, 11, 15, and 16, by using immunohistochemistry and polymerase chain reaction-single-strand conformation polymorphism/heteroduplex electrophoresis/direct sequencing, respectively. No RET mutations were found in any of the 24 CCH cases, whereas M918T mutation was detected in three concomitant MTCs. Neural cell adhesion molecule was immunoreactive in the majority of CCH associated with MTC even in the absence of morphological atypia, but not in reactive forms. The absence of RET alterations in all cases of CCH examined supports the hypothesis that the development of MTC is independent of pre-existing CCH in the nonfamilial setting; thus, sporadic CCH should not be considered a risk factor for nonfamilial MTC.
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PMID:Absence of RET gene point mutations in sporadic thyroid C-cell hyperplasia. 1738 13

Stimulation of the neural cell adhesion molecule (NCAM) by homophilic interactions is known to lead to neurite outgrowth as well as to neuronal survival. Whereas a complex network of signalling molecules is known to be of importance to NCAM-mediated neurite extension, only limited information is available regarding signalling underlying NCAM-mediated neuroprotection. Here, we present data suggesting a difference in the signalling events required for survival of rat dopaminergic neurons as compared with neurite outgrowth from the same cell type. Whereas Fyn, fibroblast growth factor receptor, mitogen-activated protein and ERK kinase, protein kinase A and protein kinase C are required for both responses to NCAM-induced signalling, phospholipase C and Ca(2+)-calmodulin-dependent kinase II are only necessary for the neurite outgrowth response, but dispensable for neuroprotection.
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PMID:Signalling pathways underlying neural cell adhesion molecule-mediated survival of dopaminergic neurons. 1740 29

The glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) belong to a structurally related family of neurotrophic factors. NTN exerts its effect through a multicomponent receptor system consisting of the GDNF family receptor alpha2 (GFR alpha2), RET, and/or NCAM (neural cell adhesion molecule). GFR alpha2 is alternatively spliced into at least three isoforms (GFR alpha2a, GFR alpha2b, and GFR alpha2c). It is currently unknown whether these isoforms share similar functional and biochemical properties. Using highly specific and sensitive quantitative real-time PCR, these isoforms were found to be expressed at comparable levels in various regions of the human brain. When stimulated with GDNF and NTN, both GFR alpha2a and GFR alpha2c, but not GFR alpha2b, promoted neurite outgrowth in transfected Neuro2A cells. These isoforms showed ligand selectivity in MAPK (mitogen-activated protein kinase) [ERK1/2 (extracellular signal-regulated kinase 1/2)] and Akt signaling. In addition, the GFR alpha2 isoforms regulated different early-response genes when stimulated with GDNF or NTN. In coexpression studies, GFR alpha2b was found to inhibit ligand-induced neurite outgrowth by GFR alpha2a and GFR alpha2c. Stimulation of GFR alpha2b also inhibited the neurite outgrowth induced by GFR alpha1a, another member of the GFR alpha. Furthermore, activation of GFR alpha2b inhibited neurite outgrowth induced by retinoic acid and activated RhoA. Together, these data suggest a novel paradigm for the regulation of growth factor signaling and neurite outgrowth via an inhibitory splice variant of the receptor. Thus, depending on the expressions of specific GFR alpha2 receptor spliced isoforms, GDNF and NTN may promote or inhibit neurite outgrowth through the multicomponent receptor complex.
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PMID:Glial cell line-derived neurotrophic factor and neurturin inhibit neurite outgrowth and activate RhoA through GFR alpha 2b, an alternatively spliced isoform of GFR alpha 2. 1752 5

Hereditary medullary thyroid carcinoma (MTC) is caused by germline mutations in the RET proto-oncogene, resulting in constitutive activation of the RET tyrosine kinase. A substantial proportion of sporadic MTCs also have RET mutations, making the RET tyrosine kinase a potential therapeutic target in MTC. We have established a transplantable MTC in nude mice from a sporadic human MTC carrying a RET C634R mutation. Transplanted tumors had an exponential growth rate with an approximate doubling time of about 3 weeks, and expressed a neuroendocrine phenotype characteristic of MTC, e.g., expression of calcitonin, chromogranin A (CgA), synaptophysin, synaptic vesicle protein 2 (SV2), vesicular monoamine transporter-1 and -2, carcinoembryonic antigen, cytokeratin 8/18, epithelial cadherin, and neural cell adhesion molecule. Plasma calcitonin and CgA levels were elevated in tumor-bearing mice and correlated with tumor size. Cytogenetic analysis, including spectral karyotyping, confirmed the human origin of the xenografted tumors and demonstrated an abnormal, near triploid karyotype. Treatment of tumor-bearing nude mice with the tyrosine kinase inhibitor ZD6474, which specifically inhibits RET, epidermal growth factor receptor (EGFR), and vascular endothelium growth factor receptor (VEGFR) tyrosine kinases, resulted in a dose-dependent inhibition of tumor growth. Oral ZD6474 given once daily (250 mg/kg, 5 days/week) reduced tumor volume to 11% when compared with controls after 4 weeks. Our results show that this transplantable MTC, designated GOT2, represents a novel and useful model for studies of MTC and RET tyrosine kinase-dependent tumor growth.
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PMID:A transplantable human medullary thyroid carcinoma as a model for RET tyrosine kinase-driven tumorigenesis. 1763 56

Since neuropathic pain is resistant to conventional analgesics such as opiates and non-steroidal anti-inflammatory drugs, the development of new types of drugs for its treatment has been awaited. Several key molecules associated with nociception have been suggested as potential targets for new analgesics. Glial cell line-derived neurotrophic factor (GDNF) has a variety of functions affecting the survival and development of specified neural cell populations, mediated via transmission of intracellular signals through binding to its high-affinity receptor, GFR*1, and subsequent activation of a tyrosine receptor kinase, RET, neural cell adhesion molecule (NCAM), or other signaling molecules. GDNF also exhibits analgesic effects in rodent models of neuropathic pain, although the underlying mechanisms are still largely unknown, including the intracellular signal transduction involved. We report here that NCAM signaling plays a role in mediating the analgesic effect of GDNF in rats with chronic constrictive injury (CCI). We found that NCAM was expressed in intrinsic neurons in the spinal dorsal horn and in dorsal root ganglion neurons with small cell bodies. Reduction of NCAM expression by NCAM antisense oligodeoxynucleotide administration to CCI rats abolished the analgesic effect of GDNF without affecting RET signaling activation. An NCAM mimetic peptide, C3d, partially reduced the chronic pain induced by CCI. These findings suggest that NCAM signaling plays a critical role in the analgesic effect of GDNF and that development of new drugs activating GDNF-NCAM signaling may represent a new strategy for the relief of intractable pain.
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PMID:Involvement of neural cell adhesion molecule signaling in glial cell line-derived neurotrophic factor-induced analgesia in a rat model of neuropathic pain. 1796 6

Whereas fibroblast growth factors (FGFs) classically transmit their signals via high-affinity tyrosine kinase receptors (FGFR1-4), recent evidence strongly implicates non-tyrosine kinase receptors (NTKR) or cell-surface FGFR-interacting proteins as important players in FGF signalling. Although NTKR have lower affinity for FGFs in comparison with cognate tyrosine kinase receptors, because of their high abundance they can effectively bind FGFs and produce unique biological effects independent of FGFRs. A prime example of such NTKR is the syndecan family of plasma membrane proteoglycans and, in particular, syndecan-4, which transmits FGF signalling via a protein kinase Calpha pathway. Another NTKR, alpha(v)beta(3) integrin, functions as an FGF signalling modulator by binding both FGF2 and FGFR1. Yet another NTKR, neural cell adhesion molecule (NCAM), can serve as an FGFR ligand and assemble an FGFR signalling complex in the absence of FGFs. Furthermore, N-cadherin, which has been reported to associate with FGFR, appears to activate FGFR in both ligand (FGF)-dependent and ligand-independent manners. Finally, gangliosides are implicated as a co-receptor system of FGFs. The biological consequence of non-canonical FGF signalling tends to be less discernable compared to the canonical FGFR activation because of the overlap between these two pathways; nevertheless, non-canonical signalling is important and sometimes essential for cellular functions. Given the diversity of FGF activities through embryonic development to adult physiology, the existence of the non-canonical signalling system may account for the different cellular response to the FGF input in different biological contexts. In this review, we will discuss recent findings related to non-canonical FGF signalling with emphasis on the endothelial biology and angiogenesis.
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PMID:Non-canonical fibroblast growth factor signalling in angiogenesis. 1805 63

A series of peptides, termed dekafins, were derived from the beta10-beta11 loop regions of fibroblast growth factors (FGFs) 1, 2, 3, 5, 6, 8, 9, 10, and 17. The dekafins share a homologous amino acid sequence similar to a sequence in the first fibronectin type III module of the neural cell adhesion molecule. All dekafins were shown by surface plasmon resonance analysis to bind fibroblast growth factor receptor (FGFR)1-IIIc-Ig2-3 and FGFR2-IIIb-Ig2-3, respectively, with K(d) values of approximately 10(-7) to 10(-8) mol/L. Binding of dekafin1 to FGFR1-IIIc-Ig2-3 was inhibited by a heparin analog, sucrose octasulfate, indicating that heparin sulfate moiety can modulate dekafin binding to FGFRs. Treatment of transcription and mRNA export (TREX) cells permanently expressing Strep-tag-labeled FGFR1-IIIc with dekafins resulted in receptor phosphorylation. FGF1-induced FGFR1-IIIc phosphorylation was inhibited by dekafin1 and 10 in high concentrations, indicating that dekafins are FGFR partial agonists. The dekafins induced neuronal differentiation as reflected by neurite outgrowth from cerebellar granule neurons, an effect that was abolished by SU5402, a specific inhibitor of the FGFR tyrosine kinase, and by inositolhexaphosphate, an extracellularly acting FGFR antagonist. Some, but not all, dekafins were capable of promoting survival of cerebellar granule neurons induced to undergo apoptosis. Thus, the dekafins are functional FGFR agonists with apparent therapeutic potential.
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PMID:Fibroblast growth factor-derived peptides: functional agonists of the fibroblast growth factor receptor. 1819 18

Activation of the fibroblast growth factor receptor (FGFR) by neural cell adhesion molecule (NCAM) is essential for NCAM-mediated neurite outgrowth. Previous peptide studies have identified two regions in the fibronectin type 3 (FN3)-like domains of NCAM as being important for these activities. Here we report the crystal structure of the NCAM FN3 domain tandem, which reveals an acutely bent domain arrangement. Mutation of a non-conserved surface residue (M610R) led to a second crystal form showing a substantially different conformation. Thus, the FN3 domain linker is highly flexible, suggesting that it corresponds to the hinge seen in electron micrographs of NCAM. The two putative FGFR1-binding segments, one in each NCAM FN3 domain, are situated close to the domain interface. They form a contiguous patch in the more severely bent conformation but become separated upon straightening of the FN3 tandem, suggesting that conformational changes within NCAM may modulate FGFR1 activation. Surface plasmon resonance experiments demonstrated only a very weak interaction between the NCAM FN3 tandem and soluble FGFR1 proteins expressed in mammalian cells (dissociation constant >100 muM). Thus, the NCAM-FGFR1 interaction at the cell surface is likely to depend upon avidity effects due to receptor clustering.
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PMID:Structure of the tandem fibronectin type 3 domains of neural cell adhesion molecule. 1826 43

We studied the histochemical phenotype of carotid body (CB) cells in the adult rat. In addition to tyrosine hydroxylase (TH), type I cells expressed numerous growth factors such as glial cell line-derived neurotrophic factor (GDNF), basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha), as well as the receptors p75, Ret, epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor-alpha (PDGFR-alpha). Type II cells expressed the glial fibrillary acid protein (GFAP), vimentin, the trophic factor bFGF and receptors p75, EGFR and PDGFR-alpha. Both types I and II cells exhibited a positive immunoreaction to markers of neural progenitor cells such as the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) and nestin, respectively, suggesting that CB contain some immature cells even at the adult stage. The possibility that these cells can be expanded and differentiated into mature neurons should be explored.
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PMID:Immunohistochemical characterization of the rat carotid body. 1828 Jul 99


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