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1.
Front Vet Sci ; 11: 1389615, 2024.
Article in English | MEDLINE | ID: mdl-38868500

ABSTRACT

Zonisamide is used in dogs for the treatment of epileptic seizures. It is predominantly metabolised by CYP450 hepatic enzymes. When used concurrently with phenobarbital (PB), zonisamide clearance is increased and its elimination half-life decreases. However, the effect that zonisamide may have on serum PB concentrations in dogs has not been previously described. Eight dogs diagnosed with idiopathic epilepsy and two dogs with structural epilepsy commenced zonisamide at 8.0 mg/kg/12 h [7.4-10 mg/kg/12 h] following an increase in the frequency of epileptic seizures. Nine dogs were receiving PB every 12 h (4.2 mg/kg/12 h [3.8-6 mg/kg/12 h]), and one dog was receiving PB every 8 h (6 mg/kg/8 h). Following the addition of zonisamide and despite no increase in PB dosage, an increase in phenobarbital serum PB concentration was observed in 9 out of 10 dogs in subsequent measurements. In five dogs, phenobarbital serum concentrations were raised to concentrations higher than the reported hepatotoxic concentrations (trough>35 mg/L). This required a reduction in daily doses of PB. This case series suggests that zonisamide affects the metabolism of PB and causes an increase in PB serum concentrations over time.

2.
Vet Rec ; 193(12): e3211, 2023 Dec 16.
Article in English | MEDLINE | ID: mdl-37503700

ABSTRACT

BACKGROUND: C-reactive protein (CRP) is an acute-phase protein produced by the liver during systemic inflammation. In humans, some epilepsies are associated with increased serum CRP (sCRP) concentrations, but this has yet to be proven in veterinary studies. Dogs with structural epilepsy (SE) and normal interictal neurological examination are hard to distinguish from dogs with idiopathic epilepsy (IE) without the use of advanced imaging. METHODS: The study included eight dogs with SE and 12 dogs with IE from a referral hospital population. This was a retrospective observational cohort study. The Mann-Whitney test was used to compare the sCRP concentrations within 24 hours of the last epileptic seizure between dogs with SE or IE. RESULTS: Dogs with SE had higher sCRP concentrations than dogs with IE (8.9 [range <2.2-53.2] mg/L vs. <2.2 [range <2.2-6.9] mg/L; p = 0.043). Five of the eight (62%) dogs with SE had an sCRP concentration above the reference interval, compared with none of the 12 dogs with IE. LIMITATIONS: The small sample size was the major limitation of this study. Other inflammatory causes were also not exclusively ruled out, although further clinical investigations were not indicated. CONCLUSIONS: This study found that sCRP concentrations were higher in this cohort of dogs with SE than in those with IE. Further studies with larger cohorts of dogs are warranted to validate if sCRP can be used as an additional biomarker for SE.


Subject(s)
Dog Diseases , Epilepsy , Humans , Dogs , Animals , C-Reactive Protein/metabolism , Cohort Studies , Dog Diseases/etiology , Epilepsy/veterinary , Epilepsy/diagnosis , Seizures/veterinary
3.
Neurobiol Aging ; 119: 22-35, 2022 11.
Article in English | MEDLINE | ID: mdl-35964541

ABSTRACT

Voice prosody measures have been linked with Alzheimer's disease (AD), but it is unclear whether they are associated with normal cognitive aging. We assessed relationships between voice measures and 10-year cognitive changes in the MIDUS national sample of middle-aged and older adults ages 42-92, with a mean age of 64.09 (standard deviation = 11.23) at the second wave. Seven cognitive tests were assessed in 2003-2004 (Wave 2) and 2013-2014 (Wave 3). Voice measures were collected at Wave 3 (N = 2585) from audio recordings of the cognitive interviews. Analyses controlled for age, education, depressive symptoms, and health. As predicted, higher jitter was associated with greater declines in episodic memory, verbal fluency, and attention switching. Lower pulse was related to greater decline in episodic memory, and fewer voice breaks were related to greater declines in episodic memory and verbal fluency, although the direction of these effects was contrary to hypotheses. Findings suggest that voice biomarkers may offer a promising approach for early detection of risk factors for cognitive impairment or AD.


Subject(s)
Alzheimer Disease , Cognitive Dysfunction , Memory, Episodic , Adult , Aged , Aged, 80 and over , Alzheimer Disease/diagnosis , Alzheimer Disease/psychology , Biomarkers , Cognition , Cognitive Dysfunction/diagnosis , Cognitive Dysfunction/etiology , Cognitive Dysfunction/psychology , Humans , Middle Aged , Neuropsychological Tests
4.
Front Vet Sci ; 9: 828083, 2022.
Article in English | MEDLINE | ID: mdl-35400094

ABSTRACT

A 14-year-old male neutered domestic short-hair cat was presented for a history of behavioral changes and episodes of urinary retention. Neurological examination was consistent with a multifocal intracranial neuroanatomical localization, with suspected right sided lateralisation and suspected raised intracranial pressure (ICP). Brain magnetic resonance imaging (MRI) revealed an intraventricular multilobulated well-defined T2W-hyperintense and T1W-isointense, markedly contrast enhancing mass lesion within the dorsal aspect of the III ventricle extending into the left lateral ventricle, causing hypertensive obstructive hydrocephalus. A ventriculoperitoneal shunt (VPS) was placed within the left lateral ventricle, followed by a radiation therapy (RT) course of 45 Gy total dose in 18 daily fractions. Six-months post-RT, computed tomography revealed mild reduction in mass size and resolution of the hydrocephalus. The patient was neurologically normal with no medical treatment. Raised ICP causes severe clinical signs, can lead to brain ischaemia and herniation, and significantly increases anesthetic risk during RT. Placement of a VPS in cats with hypertensive obstructive hydrocephalus may allow improvement of neurological signs due to raised ICP, and therefore making the patient a more stable candidate for anesthesia and radiation therapy.

5.
New Phytol ; 235(1): 234-246, 2022 07.
Article in English | MEDLINE | ID: mdl-35377486

ABSTRACT

Renewed interests in the development of bioenergy, biochemicals, and biomaterials have elicited new strategies for engineering the lignin of biomass feedstock plants. This study shows, for the first time, that 3,4-dihydroxybenzoate (DHB) is compatible with the radical coupling reactions that assemble polymeric lignin in plants. We introduced a bacterial 3-dehydroshikimate dehydratase into hybrid poplar (Populus alba × grandidentata) to divert carbon flux away from the shikimate pathway, which lies upstream of lignin biosynthesis. Transgenic poplar wood had up to 33% less lignin with p-hydroxyphenyl units comprising as much as 10% of the lignin. Mild alkaline hydrolysis of transgenic wood released fewer ester-linked p-hydroxybenzoate groups than control trees, and revealed the novel incorporation of cell-wall-bound DHB, as well as glycosides of 3,4-dihydroxybenzoic acid (DHBA). Two-dimensional nuclear magnetic resonance (2D-NMR) analysis uncovered DHBA-derived benzodioxane structures suggesting that DHB moieties were integrated into the lignin polymer backbone. In addition, up to 40% more glucose was released from transgenic wood following ionic liquid pretreatment and enzymatic hydrolysis. This work highlights the potential of diverting carbon flux from the shikimate pathway for lignin engineering and describes a new type of 'zip-lignin' derived from the incorporation of DHB into poplar lignin.


Subject(s)
Lignin , Populus , Hydroxybenzoates , Lignin/metabolism , Plants, Genetically Modified/metabolism , Wood/chemistry
6.
Plant Physiol ; 188(2): 984-996, 2022 02 04.
Article in English | MEDLINE | ID: mdl-34718804

ABSTRACT

Lignin, a polyphenolic polymer, is a major chemical constituent of the cell walls of terrestrial plants. The biosynthesis of lignin is a highly plastic process, as highlighted by an increasing number of noncanonical monomers that have been successfully identified in an array of plants. Here, we engineered hybrid poplar (Populus alba x grandidentata) to express chalcone synthase 3 (MdCHS3) derived from apple (Malus domestica) in lignifying xylem. Transgenic trees displayed an accumulation of the flavonoid naringenin in xylem methanolic extracts not inherently observed in wild-type trees. Nuclear magnetic resonance analysis revealed the presence of naringenin in the extract-free, cellulase-treated xylem lignin of MdCHS3-poplar, indicating the incorporation of this flavonoid-derived compound into poplar secondary cell wall lignins. The transgenic trees also displayed lower total cell wall lignin content and increased cell wall carbohydrate content and performed significantly better in limited saccharification assays than their wild-type counterparts.


Subject(s)
Acyltransferases/genetics , Acyltransferases/metabolism , Flavanones/metabolism , Lignin/biosynthesis , Lignin/genetics , Populus/genetics , Populus/metabolism , Xylem/metabolism , Crops, Agricultural/genetics , Crops, Agricultural/metabolism , Flavanones/genetics , Gene Expression Regulation, Plant , Genes, Plant , Malus/genetics , Malus/metabolism , Plants, Genetically Modified/metabolism , Xylem/genetics
7.
J Med Internet Res ; 22(4): e15376, 2020 04 23.
Article in English | MEDLINE | ID: mdl-32324139

ABSTRACT

BACKGROUND: Although some neuropsychological (NP) tests are considered more central for the diagnosis of Alzheimer disease (AD), there is a lack of understanding about the interaction between different cognitive tests. OBJECTIVE: This study aimed to demonstrate a global view of hierarchical probabilistic dependencies between NP tests and the likelihood of cognitive impairment to assist physicians in recognizing AD precursors. METHODS: Our study included 2091 participants from the Framingham Heart Study. These participants had undergone a variety of NP tests, including Wechsler Memory Scale, Wechsler Adult Intelligence Scale, and Boston Naming Test. Heterogeneous cognitive Bayesian networks were developed to understand the relationship between NP tests and the cognitive status. The performance of probabilistic inference was evaluated by the 10-fold cross validation. RESULTS: A total of 4512 NP tests were used to build the Bayesian network for the dementia diagnosis. The network demonstrated conditional dependency between different cognitive functions that precede the development of dementia. The prediction model reached an accuracy of 82.24%, with sensitivity of 63.98% and specificity of 92.74%. This probabilistic diagnostic system can also be applied to participants that exhibit more heterogeneous profiles or with missing responses for some NP tests. CONCLUSIONS: We developed a probabilistic dependency network for AD diagnosis from 11 NP tests. Our study revealed important psychological functional segregations and precursor evidence of AD development and heterogeneity.


Subject(s)
Alzheimer Disease/diagnosis , Cognition/physiology , Longitudinal Studies , Neuropsychological Tests/standards , Aged , Aged, 80 and over , Female , Humans , Male
8.
Evol Appl ; 13(1): 48-61, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31892943

ABSTRACT

Identifying genetic variants responsible for phenotypic variation under selective pressure has the potential to enable productive gains in natural resource conservation and management. Despite this potential, identifying adaptive candidate loci is not trivial, and linking genotype to phenotype is a major challenge in contemporary genetics. Many of the population genetic approaches commonly used to identify adaptive candidates will simultaneously detect false positives, particularly in nonmodel species, where experimental evidence is seldom provided for putative roles of the adaptive candidates identified by outlier approaches. In this study, we use outcomes from population genetics, phenotype association, and gene expression analyses as multiple lines of evidence to validate candidate genes. Using lodgepole and jack pine as our nonmodel study species, we analyzed 17 adaptive candidate loci together with 78 putatively neutral loci at 58 locations across Canada (N > 800) to determine whether relationships could be established between these candidate loci and phenotype related to mountain pine beetle susceptibility. We identified two candidate loci that were significant across all population genetic tests, and demonstrated significant changes in transcript abundance in trees subjected to wounding or inoculation with the mountain pine beetle fungal associate Grosmannia clavigera. Both candidates are involved in central physiological processes that are likely to be invoked in a trees response to stress. One of these two candidate loci showed a significant association with mountain pine beetle attack status in lodgepole pine. The spatial distribution of the attack-associated allele further coincides with other indicators of susceptibility in lodgepole pine. These analyses, in which population genetics was combined with laboratory and field experimental validation approaches, represent first steps toward linking genetic variation to the phenotype of mountain pine beetle susceptibility in lodgepole and jack pine, and provide a roadmap for more comprehensive analyses.

9.
Alzheimers Dement (N Y) ; 5: 264-271, 2019.
Article in English | MEDLINE | ID: mdl-31304232

ABSTRACT

INTRODUCTION: Despite the availability of age- and education-adjusted standardized scores for most neuropsychological tests, there is a lack of objective rules in how to interpret multiple concurrent neuropsychological test scores that characterize the heterogeneity of Alzheimer's disease. METHODS: Using neuropsychological test scores of 2091 participants from the Framingham Heart Study, we devised an automated algorithm that follows general diagnostic criteria and explores the heterogeneity of Alzheimer's disease. RESULTS: We developed a series of stepwise diagnosis rules that evaluate information from multiple neuropsychological tests to produce an intuitive and objective Alzheimer's disease dementia diagnosis with more than 80% accuracy. DISCUSSION: A data-driven stepwise diagnosis system is useful for diagnosis of Alzheimer's disease from neuropsychological tests. It demonstrated better performance than the traditional dichotomization of individuals' performance into satisfactory and unsatisfactory outcomes, making it more reflective of dementia as a spectrum disorder. This algorithm can be applied to both within clinic and outside-of-clinic settings.

10.
Curr Opin Biotechnol ; 56: 147-155, 2019 04.
Article in English | MEDLINE | ID: mdl-30529238

ABSTRACT

Lignocellulosic biomass represents an abundant source of cellulosic fibres and fermentable sugars. However, lignin, a polyphenolic constituent of secondary-thickened plant cell walls significantly contributes to biomass recalcitrance during industrial processing. Efforts to reduce plant total lignin content through genetic engineering have improved processing efficiency, but often incur an agronomic penalty. Alternatively, modifications that alter the composition of lignin and/or its interaction with other cell wall polymers display improved processing efficiency without compromising biomass yield. We propose that future efforts to improve woody feedstocks should focus on altering lignin composition and cell wall ultrastructure. Here, we describe potential future modifications to lignin and/or other cell wall characteristics that may serve as strategic targets in the production of trees that are tailor-made for specific pretreatments and end-product applications.


Subject(s)
Biotechnology/economics , Genetic Engineering , Lignin/metabolism , Trees/genetics , Cellulose/metabolism , Lignin/chemistry , Polymerization
11.
Contemp Clin Trials ; 66: 74-79, 2018 03.
Article in English | MEDLINE | ID: mdl-29330082

ABSTRACT

Patient recruitment is widely recognized as a key determinant of success for clinical trials. Yet a substantial number of trials fail to reach recruitment goals-a situation that has important scientific, financial, ethical, and policy implications. Further, there are important effects on stakeholders who directly contribute to the trial including investigators, sponsors, and study participants. Despite efforts over multiple decades to identify and address barriers, recruitment challenges persist. To advance a more comprehensive approach to trial recruitment, the Clinical Trials Transformation Initiative (CTTI) convened a project team to examine the challenges and to issue actionable, evidence-based recommendations for improving recruitment planning that extend beyond common study-specific strategies. We describe our multi-stakeholder effort to develop a framework that delineates three areas essential to strategic recruitment planning efforts: (1) trial design and protocol development, (2) trial feasibility and site selection, and (3) communication. Our recommendations propose an upstream approach to recruitment planning that has the potential to produce greater impact and reduce downstream barriers. Additionally, we offer tools to help facilitate adoption of the recommendations. We hope that our framework and recommendations will serve as a guide for initial efforts in clinical trial recruitment planning irrespective of disease or intervention focus, provide a common basis for discussions in this area and generate targets for further analysis and continual improvement.


Subject(s)
Clinical Trials as Topic , Patient Selection , Stakeholder Participation , Biomedical Research , Guidelines as Topic , Humans
12.
Appl Physiol Nutr Metab ; 42(5): 517-522, 2017 May.
Article in English | MEDLINE | ID: mdl-28177720

ABSTRACT

It is recommended that soccer players consume a high carbohydrate diet to augment performance. However, growing evidence suggests that there is a link between high free-sugar (FS) intake (>5% total energy intake; TEI) and metabolic diseases. Furthermore, foods that are often high in sugar, such as processed foods, are typically lacking in nutrient quality. We therefore analysed total-sugar, FS, dietary fibre, and micronutrient intake of players from an English Premier League academy under (U) 18 (n = 13), U15/16 (n = 25), and U13/14 (n = 21) using a 7-day food diary. Data were compared with current United Kingdom (UK) dietary reference value (DRV) for FS via a t test. The U13/14s (10% ± 18%) and U15/16s (11% ± 30%) both consumed higher amounts of FS in comparison with the UK DRV of 5% TEI (P < 0.01); conversely, the U18s did not exceed the DRV (5% ± 13%). Furthermore, FS intake of the U18s was significantly lower than the U13/14s and U15/16s (P < 0.01). Dietary fibre was below the DRV (25 g/day for U13/14 and U15/16s; 30 g/day for U18s) for all squads (19.0 ± 4.7, 19.6 ± 8.3, 17.1 ± 4.2 g/day, respectively), but not different between squads. Additionally, micronutrient reference intakes were generally met. In conclusion, we provide novel data on dietary sugar, fibre, and micronutrient intake within elite youth soccer players. We report an apparent "nutritional transition" from schoolboy to fulltime soccer player, with U18s showing a significantly lower intake of sugar in comparison with younger squads, and a similar intake of FS to the UK DRVs. Practitioners should target improving player education around sugar and fibre consumption.


Subject(s)
Athletes , Diet/standards , Dietary Carbohydrates/analysis , Dietary Fiber/analysis , Micronutrients/administration & dosage , Nutrition Assessment , Adolescent , Adolescent Nutritional Physiological Phenomena , Aging , Child , Child Nutritional Physiological Phenomena , Humans , Male , Nutritional Requirements , Soccer , United Kingdom
13.
Int J Sport Nutr Exerc Metab ; 26(5): 473-480, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27633998

ABSTRACT

While traditional approaches to dietary analysis in athletes have focused on total daily energy and macronutrient intake, it is now thought that daily distribution of these parameters can also influence training adaptations. Using 7-day food diaries, we quantified the total daily macronutrient intake and distribution in elite youth soccer players from the English Premier League in U18 (n = 13), U15/16 (n = 25) and U13/14 squads (n = 21). Total energy (43.1 ± 10.3, 32.6 ± 7.9, 28.1 ± 6.8 kcal·kg-1·day-1), CHO (6 ± 1.2, 4.7 ± 1.4, 3.2 ± 1.3 g·kg-1·day-1) and fat (1.3 ± 0.5, 0.9 ± 0.3, 0.9 ± 0.3 g·kg-1·day-1) intake exhibited hierarchical differences (p < .05) such that U13/14 > U15/16 > U18. In addition, CHO intake in U18s was lower (p < .05) at breakfast, dinner and snacks when compared with both squads but no differences were apparent at lunch. Furthermore, the U15/16s reported lower relative daily protein intake than the U13/14s and U18s (1.6 ± 0.3 vs. 2.2 ± 0.5, 2.0 ± 0.3 g·kg-1). A skewed distribution (p < .05) of daily protein intake was observed in all squads, with a hierarchical order of dinner (~0.6 g·kg-1) > lunch (~0.5 g·kg-1) > breakfast (~0.3 g·kg-1). We conclude elite youth soccer players do not meet current CHO guidelines. Although daily protein targets are achieved, we report a skewed daily distribution in all ages such that dinner > lunch > breakfast. Our data suggest that dietary advice for elite youth players should focus on both total daily macronutrient intake and optimal daily distribution patterns.


Subject(s)
Dietary Carbohydrates/analysis , Dietary Fats/analysis , Dietary Proteins/analysis , Energy Intake , Nutritional Requirements , Soccer , Adolescent , Athletes , Body Height , Body Mass Index , Body Weight , Breakfast , Diet Records , Dietary Carbohydrates/administration & dosage , Dietary Fats/administration & dosage , Dietary Proteins/administration & dosage , Humans , Lunch , Male , Meals , Nutrition Assessment , Pilot Projects , Snacks
14.
Cell Stem Cell ; 1(4): 443-57, 2007 Oct 11.
Article in English | MEDLINE | ID: mdl-18371380

ABSTRACT

Individuals with neurofibromatosis type 1 (NF1) develop abnormalities of both neuronal and glial cell lineages, suggesting that the NF1 protein neurofibromin is an essential regulator of neuroglial progenitor function. In this regard, Nf1-deficient embryonic telencephalic neurospheres exhibit increased self-renewal and prolonged survival as explants in vivo. Using a newly developed brain lipid binding protein (BLBP)-Cre mouse strain to study the role of neurofibromin in neural progenitor cell function in the intact animal, we now show that neuroglial progenitor Nf1 inactivation results in increased glial lineage proliferation and abnormal neuronal differentiation in vivo. Whereas the glial cell lineage abnormalities are recapitulated by activated Ras or Akt expression in vivo, the neuronal abnormalities were Ras- and Akt independent and reflected impaired cAMP generation in Nf1-deficient cells in vivo and in vitro. Together, these findings demonstrate that neurofibromin is required for normal glial and neuronal development involving separable Ras-dependent and cAMP-dependent mechanisms.


Subject(s)
Cell Differentiation , Cyclic AMP/metabolism , Neurofibromin 1/metabolism , Neuroglia/cytology , Neurons/cytology , Stem Cells/cytology , ras Proteins/metabolism , Animals , Cell Count , Cerebral Cortex/cytology , Cerebral Cortex/embryology , Enzyme Activation , Fatty Acid-Binding Protein 7 , Fatty Acid-Binding Proteins/metabolism , Integrases/metabolism , Mice , Mice, Knockout , Nerve Tissue Proteins/metabolism , Neurites/metabolism , Neurofibromin 1/deficiency , Neuroglia/enzymology , Neurons/enzymology , Phenotype
15.
Cell Signal ; 17(7): 857-68, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15763428

ABSTRACT

Raf kinases are important intermediates in epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) mediated activation of the mitogen-activated protein kinase (MAPK) pathway. In this report, we show that the A-Raf kinase is associated with activated EGF receptor complexes and with PDGF receptor (PDGFR) complexes independent of prior PDGF treatment. The ability of A-Raf to associate with receptor tyrosine kinases could provide a Ras-GTP-independent mechanism for the membrane localization of A-Raf. Expression of a partially activated A-Raf mutant resulted in decreased tyrosine phosphorylation of the PDGFR, specifically on Y857 (autophosphorylation site) and Y1021 (phospholipase Cgamma1 (PLCgamma1) binding site), but not the binding sites for other signalling proteins (Nck, phosphatidylinositol 3'-kinase (PI3K), RasGAP, Grb2, SHP). Activated A-Raf expression also altered the activation of PLCgamma1, and p85-associated PI3K. Thus, A-Raf can regulate PLCgamma1 signalling via a PDGFR-dependent mechanism and may also regulate PI3K signalling via a PDGFR-independent mechanism.


Subject(s)
Proto-Oncogene Proteins A-raf/physiology , Receptors, Platelet-Derived Growth Factor/physiology , Animals , COS Cells , Chlorocebus aethiops , ErbB Receptors/metabolism , Humans , Mice , Mutation , NIH 3T3 Cells , Organ Specificity , Phosphatidylinositol 3-Kinases/metabolism , Phospholipase C gamma , Phosphorylation , Proto-Oncogene Proteins A-raf/genetics , Proto-Oncogene Proteins A-raf/metabolism , Proto-Oncogene Proteins c-raf/biosynthesis , Signal Transduction , Type C Phospholipases/metabolism
16.
Oncogene ; 24(11): 1946-57, 2005 Mar 10.
Article in English | MEDLINE | ID: mdl-15688033

ABSTRACT

Meningiomas are common central nervous system tumors; however, the molecular mechanisms underlying their pathogenesis are largely undefined. Previous work has implicated Protein 4.1B as an important tumor suppressor involved in the development of these neoplasms. In this report, we demonstrate that the U2 domain is necessary and sufficient for the ability of Protein 4.1B to function as a meningioma growth suppressor. Using a series of truncation and deletion constructs of DAL-1 (a fragment of Protein 4.1B that retains all the growth suppressive properties), we narrowed the domain required for 4.1B growth suppression to a fragment containing a portion of the FERM domain and the U2 domain using clonogenic assays on meningioma cells. Deletion of the U2 domain in the context of the full-length DAL-1 molecule eliminated growth suppressor function, as measured by thymidine incorporation and caspase-3 activation. Moreover, targeting the U2 domain to the plasma membrane using a membrane localization signal (MLS) reduced cell proliferation, similar to wild-type DAL-1. Collectively, the data suggest that the U2 domain, when properly targeted to the plasma membrane, contains all the residues necessary for mediating Protein 4.1B growth suppression.


Subject(s)
Cell Division , Membrane Proteins/genetics , Membrane Proteins/metabolism , Animals , Base Sequence , Cell Line, Tumor , Cell Membrane/pathology , DNA Primers , Humans , Meningeal Neoplasms , Meningioma , Polymerase Chain Reaction , Rats , Sequence Deletion , Transfection
17.
Biochem Biophys Res Commun ; 290(4): 1267-74, 2002 Feb 01.
Article in English | MEDLINE | ID: mdl-11812000

ABSTRACT

Src homology 2 (SH2) domains mediate phosphotyrosine (pY)-dependent protein:protein interactions involved in signal transduction pathways. We have found that the SH2 domains of the 85-kDa alpha subunit (p85) of phosphatidylinositol 3-kinase (PI3 kinase) bind directly to the serine/threonine kinase A-Raf. In this report we show that the p85 SH2:A-Raf interaction is phosphorylation-independent. The affinity of the p85 C-SH2 domain for A-Raf and phosphopeptide pY751 was similar, raising the possibility that a p85:A-Raf complex may play a role in the coordinated regulation of the PI3 kinase and Raf-MAP kinase pathways. We further show that the p85 C-SH2 domain contains two distinct binding sites for A-Raf; one overlapping the phosphotyrosine-dependent binding site and the other a separate phosphorylation-independent site. This is the first evidence for a second binding site on an SH2 domain, distinct from the phosphotyrosine-binding pocket.


Subject(s)
Phosphatidylinositol 3-Kinases/chemistry , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-raf/metabolism , 3T3 Cells , Amino Acid Sequence , Animals , Binding Sites , COS Cells , Mice , Models, Biological , Molecular Sequence Data , Mutagenesis , Phosphatidylinositol 3-Kinases/genetics , Phosphorylation , Proto-Oncogene Proteins A-raf , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Signal Transduction , src Homology Domains
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