Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four isoforms of the catalytic alpha subunit of the Na,K-ATPase have been previously identified. We characterized and mapped a genomic copy of the human ATP1A4 isoform between D1S2707 and WI-9524, telomeric to a nearby isoform ATP1A2, and within a candidate region at 1q23 for familial hemiplegic migraine (FHM). Human ATP1A4 gene shares 84% identity with the mouse Atp1a4 gene, and both consist of 22 exons and 21 introns. The predicted polypeptide is 1029 amino acids and shares 82 and 79.8% identity, respectively, with human ATP1A2 and ATP1A1. ATP1A4 is larger than other isoforms and most divergent at the N-terminus. ATP1A4 and ATP1A2 are paralogous genes with the same number and organization of putative H-transmembrane domains, conserved exon-intron boundaries, and are found approximately 8.5 kb apart. Expression analysis of the ATP1A4 gene revealed a new major approximately 7.5 kb transcript in human skeletal muscle, with expression also shown in mouse muscle. Predictive analysis of promoter regions identified muscle specific regulatory elements for ATP1A4 and Atp1a4. Mutation analysis among eight affected individuals from a single large, highly penetrant FHM family was negative in ATP1A4 and ATP1A2 although multiple polymorphisms were identified.
...
PMID:Physical mapping and characterization of the human Na,K-ATPase isoform, ATP1A4. 1211 9

The field of migraine genetics has seen an explosion of information over the last year. In a recent breakthrough, missense mutations in a chromosome 1q23 gene, ATP1A2, encoding a Na+, K+-ATPase, have been identified in four distinct pedigrees with a rare form of familial hemiplegic migraine (FHM). ATP1A2 is expressed in the brain, like the voltage gated calcium channel gene, CACNA1A, previously identified as the first hemiplegic migraine gene (FHM1). The shared hemiplegic migraine phenotype of mutations in ATP1A2 and CACNA1A raises the possibility that they coordinately regulate ion homeostasis that determines susceptibility to the initiation of both migraine aura and the pain phase of migraine. For the more common and genetically complex forms of migraine, genome-wide screens have identified several new loci on 4q24, 6p12.2-21.1, 11q24, and 14q21.2-q22.3, suggesting additional migraine genes in these regions. In addition, a recent large case-control association study has linked single nucleotide polymorphisms in the insulin receptor/INSR gene with migraine. However, these polymorphisms do not result in detectable changes in receptor function. The continuing genetic identification of key proteins involved in migraine will refine our understanding of this common and sometimes debilitating disorder, which can strike during the most productive years of a person's life. Given the co-morbidity of migraine with depression and bipolar disorder, our knowledge of the causes of migraine may also contribute to our understanding of these disorders.
...
PMID:Update on the genetics of migraine. 1462 54

Familial hemiplegic migraine (FHM), a rare autosomal dominant subtype of migraine with aura, has been linked to two chromosomal loci, 19p13 and 1q23. Mutations in the Na+K+-ATPase alpha2 subunit gene, ATP1A2, on 1q23 have recently been shown to cause familial hemiplegic migraine type 2 (FHM2). We sequenced the coding regions of this gene in a Finnish chromosome 1q23-linked FHM family with associated symptoms such as coma and identified a novel A1033G mutation in exon 9. This mutation results in a threonine-to-alanine substitution at codon 345. This residue is located in a highly conserved N-terminal region of the M4-5 loop of the Na+,K+-ATPase. Furthermore, the T345A mutation co-segregated with the disorder in our family and was not present in 132 healthy Finnish control individuals. For these reasons it is most likely the FHM-causing mutation in this family.
...
PMID:A novel missense ATP1A2 mutation in a Finnish family with familial hemiplegic migraine type 2. 1513 18

A1A2 Na+/K+-ATPase mutations cause familial hemiplegic migraine type 2 (FHM2). The authors identified three putative A1A2 mutations (D718N, R763H, P979L) and three that await validation (P796R, E902K, X1021R). Ten to 20% of FHM cases may be FHM2. A1A2 mutations have a penetrance of about 87%. D718N causes frequent, long-lasting HM, and P979L may cause recurrent coma. D718N and P979L may predispose to seizures and mental retardation. A1A2 does not play a major role in sporadic HM; only one variant, R383H, occurred in 1 of 24 cases.
...
PMID:Variability of familial hemiplegic migraine with novel A1A2 Na+/K+-ATPase variants. 1515 95

A number of missense mutations in the ATP1A2 gene, which encodes the Na,K-ATPase alpha2 subunit, have been identified in familial hemiplegic migraine with aura. Loss of function and haploinsufficiency have been the suggested mechanisms in mutants for which functional analysis has been reported. This paper describes a kinetic analysis of mutant T345A, recently identified in a detailed genetic analysis of a large Finnish family (Kaunisto, M. A., Harno, H., Vanmolkot, K. R., Gargus, J. J., Sun, G., Hamalainen, E., Liukkonen, E., Kallela, M., van den Maagdenberg, A. M., Frants, R. R., Farkkila, M., Palotie, A., and Wessman, M. (2004) Neurogenetics 5, 141-146). Introducing T345A into the conserved rat alpha2 enzyme does not alter cell growth or catalytic turnover but causes a substantial decrease in apparent K+ affinity (2-fold increase in K0.5(K+)). In view of the location of Thr-345 in the cytoplasmic stalk domain adjacent to transmembrane segment 4, the 2-fold increase in K0.5(K+) is probably due to T345A replacement altering K+ occlusion/deocclusion. Faster K+ deocclusion of the mutant via the E2(K) + ATP --> E1.ATP + K+ partial reaction is evidenced in (i) a marked increase (300%) in K+ stimulation of Na-ATPase at micromolar ATP, (ii) a 4-fold decrease in KATP, and (iii) only a modest increase (approximately 3-fold) in I50 for vanadate, which was used as a probe of the steady state E1/E2 conformational equilibrium. We suggest that the decreased apparent K+ affinity is the basis for a reduced rate of extracellular K+ removal, which delays the recovery phase of nerve impulse transmission in the central nervous system and, thereby, the clinical picture of migraine with aura. This is the first demonstration of a mutation that leads to a disease associated with a kinetically altered but fully functional Na,K-ATPase, refining the molecular mechanism of pathogenesis in familial hemiplegic migraine.
...
PMID:Kinetic alterations due to a missense mutation in the Na,K-ATPase alpha2 subunit cause familial hemiplegic migraine type 2. 1530 25

Our knowledge about migraine pathogenesis has increased exponentially over the last decade and this greatly due to the advances in genetics. In familial hemiplegic migraine (FHM), the findings of mutations in the CACNA1A gene (19p13), coding for the pore-forming subunit (alpha1A) of neuronal voltage-dependent P/Q-type calcium channels (FHM1), and in the ATP1A2 gene (1q21-23), encoding the alpha2-subunit of the Na+, K+ ATPase ionic pump (FHM2) have focused attention on central nervous system ionic channels and helped to better understand FHM pathophysiology. A dysfunction of these channels modifies neuronal excitability (favouring spreading depression), chemical neurotransmission and, indirectly, neuronal metabolism. These channels may represent targets for novel anti-migraine drugs, which underscores their importance for the frequent forms of migraine (without or with aura). Studies of gene associations, neuromuscular transmission, cerebellar functions, neuronal excitability and metabolism and certain drug effects suggest indeed that ionic channels play a pathogenic role in migraine with aura patients. However, in the majority of patients they are probably not the sole culprit, since most of the frequent forms of migraine seem to have a more complex genetic predisposition based on a number of single nucleotide polymorphisms. The challenge for the next decade is to establish correlations between the geno- and the phenotype of migraine patients which needs more frequent and focused genetic studies and a more precise phenotype, based on clinical as well as on neurophysiologic and metabolic data.
...
PMID:[Genetics of migraines: from ionic channels to single nucleotide polymorphisms?]. 1534 75

Familial hemiplegic migraine (FHM) is an autosomal dominant subtype of migraine with hemiparesis during the aura. In over 50% of cases the causative gene is CACNA1A (FHM1), which in some cases produces a phenotype with cerebellar signs, including ataxia and nystagmus. Recently, mutations in ATP1A2 on chromosome 1q23 encoding a Na+/K+ -ATPase subunit were identified in four families (FHM2). We now describe an FHM2 pedigree with a fifth ATP1A2 mutation coding for a G301R substitution. The phenotype was particularly severe and included hemiplegic migraine, seizure, prolonged coma, elevated temperature, sensory deficit, and transient or permanent cerebellar signs, such as ataxia, nystagmus, and dysarthria. A mild crossed cerebellar diaschisis during an attack further supported the clinical evidence of a cerebellar deficit. This is the first report suggesting cerebellar involvement in FHM2. A possible role for CACNA1A in producing the phenotype in this family was excluded by linkage studies to the FHM1 locus. The study of this family suggests that the absence of cerebellar signs may not be a reliable indicator to clinically differentiate FHM2 from FHM1.
...
PMID:A G301R Na+/K+ -ATPase mutation causes familial hemiplegic migraine type 2 with cerebellar signs. 1545 25

Within the past decade it has been possible to identify susceptibility gene loci that predispose to migraine using genetic markers distributed across the human genome. Five new loci with significant linkage to common types of migraine--migraine with or without aura--have been identified on four different chromosomes using a genome-wide screen approach. So far, only the locus on 4q has been replicated but no specific, disease-causing mutations have been described in these common forms of migraine. The best genetic evidence providing molecular insight into migraine still comes from the mutations detected in a rare Mendelian form of migraine with aura--familial hemiplegic migraine (FHM). In 50%-70% of FHM families, mutations in the calcium channel gene CACNA1A in chromosome 19p13 have been identified. In some families, mutations in the ATP1A2 gene encoding the alpha2 subunit of the Na+, K+-ATPase are associated with FHM, linked to 1q23. Here we discuss the current knowledge of the heritability of migraine and rare migraine variants as models for understanding the pathophysiology of common migraine and animal models that might contribute to understanding common forms of migraine.
...
PMID:The molecular genetics of migraine. 1551 97

Alternating hemiplegia of childhood (AHC) is a rare disorder mainly characterised by attacks of hemiplegia and mental retardation. AHC has often been associated with migraine. Previously, we have excluded the involvement of the familial hemiplegic migraine (FHM) CACNA1A gene in four patients with AHC. A second gene for FHM was discovered recently: the ATP1A2 gene on chromosome 1q23, coding for the alpha 2 subunit of Na+,K+-ATPase. We performed a mutation analysis of the ATP1A2 gene in six patients, using direct sequencing, but found no mutations in any of the 23 exons. Other cerebral ion channel genes remain candidate genes for AHC.
...
PMID:Alternating hemiplegia of childhood: no mutations in the second familial hemiplegic migraine gene ATP1A2. 1553 63

Migraine is a common form of the chronic headache syndromes. Although the pathogenesis of migraine still remains enigmatic, there have been remarkable progress in headache research. Point mutations of P/Q-type Ca2+ channel alpha 1 subunit (CACNA1A) gene have been identified in familial hemiplegic migraine (FHM), which linked to chromosome 19 (FHM-1, OMIM 141500). Na-K ATPase alpha2 gene has been identified as the causative gene for FHM linked to 1q21-23 (FHM-2, OMIM 602481). Common forms of migraine (i.e. migraine with and without aura) seems to be caused from multifactorial genetic factors and environmental factors. An association study of allelic variation at Codon 23 (Cys or Ser) of 5HT2C-R gene in Japanese samples revealed that the Ser allele frequency in migraine with aura was significantly higher than that in the non-headache controls. However, negative association of this polymorphism have been reported in Caucasian migrainures. The C677T allelic variation of 5,10-methylenetetrahydrofolate reductase (MTHFR) are focused on in association with the coronary heart diseases and the cerebrovascular diseases. The T allelic frequency in migraine sufferers was significantly higher than that in controls. The C677T mutation of MTHFR is one of the genetic risk factors for migraine. These observations are confirmed in Turkish, Australian and Spanish samples. Positive associations of angiotensin converting enzyme (ACE) gene, endotheline receptor-A (ET-A) gene, and insulin receptor gene have been reported. Using the genomewide screen technology, significant linkage between the migraine with aura and a marker on 4q24 has been reported in Finnish families. The genome wide screen analysis will be one of the powerful strategies on exploring migraine gene. Genetic study of migraine headache is a promised and fruitful field and will provide deep understanding to migraine headache. Discovery of new responsible or susceptible genes to migraine will also open an avenue to develop new therapeutic strategy of migraine.
...
PMID:[An update on the familial headache syndromes]. 1565 39


1 2 3 4 5 Next >>

---