Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
 19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder primarily affecting motor neurons. The etiology of the majority of cases remains unknown. Recent findings from several laboratories suggest a role for neurofilaments in the development of motor neuron disorders. The C-terminal region of the human neurofilament heavy subunit (NEFH) contains a unique functional domain consisting of 43 repeat motifs of the amino acids Lys-Ser-Pro (KSP). This C-terminal region of NEFH forms the sidearm projections which cross-link the neurofilaments. Previously, we have demonstrated polymorphism in the C-terminal region of the human NEFH: an allelic variant of a slightly larger molecular size, containing an additional KSP phosphorylation motif. Novel mutations in this region were found in five ALS patients. We propose that changes in the KSP-repeat domain may affect the cross-linking properties of the heavy neurofilament subunit and perhaps contribute to the development of neurofilamentous swellings in motor neurons, a hallmark of ALS.
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PMID:Variants of the heavy neurofilament subunit are associated with the development of amyotrophic lateral sclerosis. 784 98

We examined the neurofilament heavy subunit (NEFH) as a candidate gene for familial amyotrophic lateral sclerosis. We screened the KSP repeat region of the NEFH gene in 117 unrelated individuals who inherited familial amyotrophic lateral sclerosis as an autosomal trait but who do not have the mutation in the SOD1 locus, and we found no variants in any individual. We conclude that the motor neuron degeneration observed in non-SOD1 familial amyotrophic lateral sclerosis is not due to mutations in the KSP repeat of the NEFH gene.
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PMID:Analysis of the KSP repeat of the neurofilament heavy subunit in familiar amyotrophic lateral sclerosis. 861 84

This article reviews current knowledge of neurofilament structure, phosphorylation, and function and neurofilament involvement in disease. Neurofilaments are obligate heteropolymers requiring the NF-L subunit together with either the NF-M or the NF-H subunit for polymer formation. Neurofilaments are very dynamic structures; they contain phosphorylation sites for a large number of protein kinases, including protein kinase A (PKA), protein kinase C (PKC), cyclin-dependent kinase 5 (Cdk5), extracellular signal regulated kinase (ERK), glycogen synthase kinase-3 (GSK-3), and stress-activated protein kinase gamma (SAPK gamma). Most of the neurofilament phosphorylation sites, located in tail regions of NF-M and NF-H, consist of the repeat sequence motif, Lys-Ser-Pro (KSP). In addition to the well-established role of neurofilaments in the control of axon caliber, there is growing evidence based on transgenic mouse studies that neurofilaments can affect the dynamics and perhaps the function of other cytoskeletal elements, such as microtubules and actin filaments. Perturbations in phosphorylation or in metabolism of neurofilaments are frequently observed in neurodegenerative diseases. A down-regulation of mRNA encoding neurofilament proteins and the presence of neurofilament deposits are common features of human neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Parkinson's disease, and Alzheimer's disease. Although the extent to which neurofilament abnormalities contribute to pathogenesis in these human diseases remains unknown, emerging evidence, based primarily on transgenic mouse studies and on the discovery of deletion mutations in the NF-H gene of some ALS eases, suggests that disorganized neurofilaments can provoke selective degeneration and death of neurons. An interference of axonal transport by disorganized neurofilaments has been proposed as one possible mechanism of neurofilament-induced pathology. Other factors that can potentially lead to the accumulation of neurofilaments will be discussed as well as the emerging evidence for neurofilaments as being possible targets of oxidative damage by mutations in the superoxide dismutase enzyme (SOD1); such mutations are responsible for approximately 20% of familial ALS cases.
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PMID:Neurofilaments in health and disease. 975 17

The abnormal assembly and accumulation of neurofilaments (NF) in the perikarya and proximal axons of motor neurones is a characteristic of ALS. Deletions in the KSP repeat region of the NF-H gene have previously been reported in seven patients with sporadic ALS. Here we report the identification of a novel 84 bp insertion in the NF-H gene. This leads to an extra four KSP repeat elements in a highly conserved repetitive region of the gene. Although neurofilament mutations are only associated with a very small proportion of ALS cases, this insertion provides further support of a role for neurofilaments in the pathogenesis of ALS.
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PMID:Novel insertion in the KSP region of the neurofilament heavy gene in amyotrophic lateral sclerosis (ALS). 987 37

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron degeneration resulting in paralysis and death, usually within 3 years of onset. Pathological and animal studies implicate neurofilament involvement in ALS, but whether this is primary or secondary is not clear. The heavy neurofilament subunit (NFH) tail is composed of a repeating amino acid motif, usually X-lysine-serine-proline-Y-lysine (XKSPYK), where X is a single amino acid and Y is one to three amino acids. There are two common polymorphic variants of 44 or 45 repeats. The tail probably regulates axonal calibre, with interfilament spacing determined by phosphorylation of the KSP motifs. A previous study suggested an association between sporadic cases of ALS and NFH tail deletions, but two subsequent studies have found none. We have analysed samples from two different populations (UK 207, Scandinavia 323) with age-matched controls for each group (UK 219, Scandinavia 228) and have found four novel NFH tail deletions, each involving a whole motif. These were found in three patients with sporadic ALS and a family with autosomal dominant ALS, although another was also found in two young controls. In all cases motif deletions were only associated with disease when paired with the long NFH allele. The deletions all occurred within a small region of the NFH tail. This has allowed us to propose a structural organization of the tail as well as allowing observed deletions both from this study and previous reports to be organized into logical groups. These results strongly suggest that NFH motif deletions can be a primary event in ALS but that they are not common.
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PMID:Deletions of the heavy neurofilament subunit tail in amyotrophic lateral sclerosis. 993 23

Neurofilaments are neuron-specific intermediate filaments. They are classed into three groups according to their molecular masses: neurofilament heavy, middle and light chains (NF-H, NF-M and NF-L). Neurofilaments assemble and form through the association of their central alpha-helical coiled-coil rod domains. NF-H and NF-M are distinct from NF-L as they contain a carboxyl-terminal tail domain, which appears to form connections with adjacent structures and other neurofilaments. Together with other axonal components such as microtubules, they form the dynamic axonal cytoskeleton. They maintain and regulate neuronal cytoskeletal plasticity through the regulation of neurite outgrowth, axonal caliber and axonal transport. Neurofilaments contain KSP repeats that are consensus motifs for the proline-directed kinases and are extensively phosphorylated in vivo, and their functions are thought to be regulated through their phosphorylation. Cyclin-dependent kinase 5 (Cdk5) is a proline-directed kinase, whose activity is restricted to the neuron through the neuronal-specific distribution of its activators p35 and p39. Cdk5 is the only kinase that affects the electrophoretic mobility of human NF-H and is thought to be the major neurofilament kinase. Cdk5 is involved in crosstalk with other signal transduction pathways such as the mitogen-activated protein kinase and myelin-associated glycoprotein pathways to influence the phosphorylation of neurofilaments and other cytoskeletal proteins. Both the hyperactivation of Cdk5 activity and subsequent hyperphosphorylation of neurofilaments and the microtubule-associated protein tau have been implicated in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease and amyotrophic lateral sclerosis. Here we review the functions of neurofilaments and the significance of Cdk5 phosphorylation of neurofilaments.
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PMID:Cyclin-dependent kinase 5 in neurofilament function and regulation. 1467 12

Aberrant phosphorylation of neuronal cytoskeletal proteins is a key pathological event in neurodegenerative disorders such as Alzheimer disease (AD) and amyotrophic lateral sclerosis, but the underlying mechanisms are still unclear. Previous studies have shown that Pin1, a peptidylprolyl cis/trans-isomerase, may be actively involved in the regulation of Tau hyperphosphorylation in AD. Here, we show that Pin1 modulates oxidative stress-induced NF-H phosphorylation. In an in vitro kinase assay, the addition of Pin1 substantially increased phosphorylation of NF-H KSP repeats by proline-directed kinases, Erk1/2, Cdk5/p35, and JNK3 in a concentration-dependent manner. In vivo, dominant-negative (DN) Pin1 and Pin1 small interfering RNA inhibited epidermal growth factor-induced NF-H phosphorylation. Because oxidative stress plays an important role in the pathogenesis of neurodegenerative diseases, we studied the role of Pin1 in stressed cortical neurons and HEK293 cells. Both hydrogen peroxide (H(2)O(2)) and heat stresses induce phosphorylation of NF-H in transfected HEK293 cells and primary cortical cultures. Knockdown of Pin1 by transfected Pin1 short interference RNA and DN-Pin1 rescues the effect of stress-induced NF-H phosphorylation. The H(2)O(2) and heat shock induced perikaryal phospho-NF-H accumulations, and neuronal apoptosis was rescued by inhibition of Pin1 in cortical neurons. JNK3, a brain-specific JNK isoform, is activated under oxidative and heat stresses, and inhibition of Pin1 by Pin1 short interference RNA and DN-Pin1 inhibits this pathway. These results implicate Pin1 as a possible modulator of stress-induced NF-H phosphorylation as seen in neurodegenerative disorders like AD and amyotrophic lateral sclerosis. Thus, Pin1 may be a potential therapeutic target for these diseases.
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PMID:Pin1-dependent prolyl isomerization modulates the stress-induced phosphorylation of high molecular weight neurofilament protein. 1863 47

Aberrant hyperphosphorylation of neuronal cytoskeletal proteins is one of the major pathological hallmarks of neurodegenerative disorders such as Alzheimer disease (AD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). Human NF-M/H display a large number of multiple KSP repeats in the carboxy-terminal tail domain, which are phosphorylation sites of proline-directed serine/threonine (pSer/Thr-Pro, KS/T-P) kinases. The phosphorylation sites of NF-M/H have not been characterized in AD brain. Here, we use quantitative phosphoproteomic methodology, isobaric tag for relative and absolute quantitation (iTRAQ), for the characterization of NF-M/H phosphorylation sites in AD brain. We identified 13 hyperphosphorylated sites of NF-M; 9 Lys-Ser-Pro (KSP) sites; 2 variant motifs, Glu-Ser-Pro (ESP) Ser-736 and Leu-Ser-Pro (LSP) Ser-837; and 2 non-S/T-P motifs, Ser-783 and Ser-788. All the Ser/Thr residues are phosphorylated at significantly greater abundance in AD brain compared with control brain. Ten hyperphosphorylated KSP sites have been identified on the C-terminal tail domain of NF-H, with greater abundance of phosphorylation in AD brain compared with control brain. Our data provide the direct evidence that NF-M/H are hyperphosphorylated in AD compared with control brain and suggest the role of both proline-directed and non-proline-directed protein kinases in AD. This study represents the first comprehensive iTRAQ analyses and quantification of phosphorylation sites of human NF-M and NF-H from AD brain and suggests that aberrant hyperphosphorylation of neuronal intermediate filament proteins is involved in AD.
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PMID:Quantitative phosphoproteomic analysis of neuronal intermediate filament proteins (NF-M/H) in Alzheimer's disease by iTRAQ. 2062 30