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1.
Artigo em Inglês | MEDLINE | ID: mdl-38230914

RESUMO

BACKGROUND: Speech and language therapists (SLTs) and care home activities staff play key roles in managing and supporting the communication needs of older residents in care homes. However, the current practice and perspectives of these two professions in the United Kingdom has not been examined. AIMS: To investigate the practice patterns and views of SLTs and activities staff working in UK care homes for older adults in relation to residents' communication needs. METHODS AND PROCEDURES: Two online surveys, with 63 questions (SLT survey) and 46 questions (activities staff survey) in total, were created using the online platform Qualtrics. Participants were asked to consider their routine practice before COVID-19. Results were analysed using descriptive statistics and qualitative content analysis. OUTCOMES AND RESULTS: A total of 116 valid responses were received from SLTs and 29 valid responses from activities staff. A high level of communication needs in care homes was reported by both participant groups, as was insufficient time and resources and lack of managerial encouragement in this area. SLTs reported that the majority of referrals to their service from care homes was for swallowing needs (70%). Cognitive communication difficulty was the most commonly reported communication need by SLTs (65%). Most SLTs (73%-87%) provided some level of communication intervention and considered management of residents' communication needs to be both part of the SLT role and a good investment of their time. Lack of confidence setting goals and providing direct intervention for communication needs was reported, with 25% feeling stressed at the thought of this. The main themes from free text responses about SLT service improvement were increased staff training, funding (of resources and specialist posts) and changes to service provision (referral criteria and accessibility/awareness of SLT service). Hearing impairment was the communication need most commonly reported by activities staff (43%). Participants demonstrated relatively high awareness of communication difficulty in residents and reported high levels of knowledge and confidence identifying and supporting residents' communication. Most (79%-89%) considered identifying and supporting the communication needs of residents to be part of their role and expressed interest in receiving further training in communication support. The reported activities staff data set may be positively biased. CONCLUSIONS AND IMPLICATIONS: SLTs and activities staff were highly motivated to support the communication needs of care home residents. Increased training, time and resources dedicated to managing the communication needs of residents emerged as opportunities for service improvement across both data sets. WHAT THIS PAPER ADDS: What is already known on the subject There is a high level of communication need amongst older care home residents. Social interaction and relationships are important factors contributing to quality of life in this population and rely on successful communication. Speech and language therapists (SLTs) and activities staff play key roles in managing and supporting the communication needs of this client group, but the current practice and perspectives of these professions in the United Kingdom has not been examined. What this study adds A high level of communication need in care home residents was identified by both SLT and activities staff and both participant groups were motivated to address, identify and manage this need. However, insufficient time and resources, as well as a perceived lack of encouragement from managers to provide communication support/intervention, were reported by both groups. SLT practice was constrained by referral criteria and care pathways, which differed between services. Suggestions for SLT service improvement are reported. Clinical implications of this study Targeted, ongoing staff training is required in care homes to improve the communication environment and develop care home staff capacity to support residents' communication needs. There is also a call for service level improvements to increase the range of SLT practice in care homes, including a greater focus on communication needs and more specialist (e.g., dementia) SLT roles.

2.
ACS Synth Biol ; 12(1): 153-163, 2023 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-36623275

RESUMO

Botulinum neurotoxin serotype A (BoNT/A) is a widely used cosmetic agent that also has diverse therapeutic applications; however, adverse antidrug immune responses and associated loss of efficacy have been reported in clinical uses. Here, we describe computational design and ultrahigh-throughput screening of a massive BoNT/A light-chain (BoNT/A-LC) library optimized for reduced T cell epitope content and thereby dampened immunogenicity. We developed a functional assay based on bacterial co-expression of BoNT/A-LC library members with a Förster resonance energy transfer (FRET) sensor for BoNT/A-LC enzymatic activity, and we employed high-speed fluorescence-activated cell sorting (FACS) to identify numerous computationally designed variants having wild-type-like enzyme kinetics. Many of these variants exhibited decreased immunogenicity in humanized HLA transgenic mice and manifested in vivo paralytic activity when incorporated into full-length toxin. One variant achieved near-wild-type paralytic potency and a 300% reduction in antidrug antibody response in vivo. Thus, we have achieved a striking level of BoNT/A-LC functional deimmunization by combining computational library design and ultrahigh-throughput screening. This strategy holds promise for deimmunizing other biologics with complex superstructures and mechanisms of action.


Assuntos
Anticorpos , Camundongos , Animais , Camundongos Transgênicos , Biblioteca Gênica , Domínios Proteicos
3.
Sci Rep ; 12(1): 7943, 2022 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-35562367

RESUMO

The product encoded by the X-linked inhibitor of apoptosis (XIAP) gene is a multi-functional protein which not only controls caspase-dependent cell death, but also participates in inflammatory signalling, copper homeostasis, response to hypoxia and control of cell migration. Deregulation of XIAP, either by elevated expression or inherited genetic deletion, is associated with several human disease states. Reconciling XIAP-dependent signalling pathways with its role in disease progression is essential to understand how XIAP promotes the progression of human pathologies. In this study we have created a panel of genetically modified XIAP-null cell lines using TALENs and CRISPR/Cas9 to investigate the functional outcome of XIAP deletion. Surprisingly, in our genetically modified cells XIAP deletion had no effect on programmed cell death, but instead the primary phenotype we observed was a profound increase in cell migration rates. Furthermore, we found that XIAP-dependent suppression of cell migration was dependent on XIAPdependent control of C-RAF levels, a protein kinase which controls cell signalling pathways that regulate the cytoskeleton. These results suggest that XIAP is not necessary for control of the apoptotic signalling cascade, however it does have a critical role in controlling cell migration and motility that cannot be compensated for in XIAP-knockout cells.


Assuntos
Linfócitos Nulos , Proteínas Proto-Oncogênicas c-raf , Apoptose , Caspases/metabolismo , Linfócitos Nulos/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , Transdução de Sinais , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo
4.
J Nat Prod ; 85(3): 540-546, 2022 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-35100504

RESUMO

The known solid-tumor-selective cytotoxin aulosirazole (1) was identified from bioactive extracts from the culture medium of the cyanobacterium Nostoc sp. UIC 10771. Here, we demonstrate that 1 induces the nuclear accumulation of FOXO3a in OVCAR3 using both Western blot analysis and immunofluorescence confocal microscopy. We also report the discovery of two additional analogues, aulosirazoles B (2) and C (3). Structures for compounds 2 and 3 were determined using HR-ESI-LC-MS/MS and 1D and 2D NMR experiments. Aulosirazoles B (2) and C (3) represent the first natural analogues of the FOXO-activating compound aulosirazole (1) and are the second and third isothiazole-containing metabolites reported from this phylum.


Assuntos
Nostoc , Neoplasias Ovarianas , Apoptose , Carcinoma Epitelial do Ovário , Linhagem Celular Tumoral , Cromatografia Líquida , Feminino , Humanos , Nostoc/química , Neoplasias Ovarianas/tratamento farmacológico , Espectrometria de Massas em Tandem , Fatores de Transcrição
5.
Int J Lang Commun Disord ; 57(1): 182-225, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34841623

RESUMO

BACKGROUND: The communication skills of older adults living in care homes is an underexplored topic. Ageing can lead to reduced communication ability and activity; and in the care home environment there may also be fewer communication opportunities. This situation is likely to negatively impact well-being. Previous reviews have found evidence of the effectiveness of behavioural interventions in increasing well-being, but no systematic review to date has focused specifically on the evidence base for group language and communication interventions in this population. AIMS: To identify and evaluate the evidence for behavioural interventions with older adults, delivered in groups in care homes, that specifically included a language or communication activity. To explore the impact of such intervention on the specific domains of language, communication and social interaction. To determine whether behavioural mechanisms of action can be identified. METHODS & PROCEDURES: Embase, Medline, Ovid Nursing database, Psych info and CINAHL complete were searched and produced 158 records for screening, of which 22 remained for review. In order to identify and evaluate the quality of the evidence base presented the following research questions were posed: What research has been conducted in this area? What is the methodological quality of the studies identified? How complete is the intervention reporting? How was change measured in the domains of language, communication and social interaction? Is there evidence of efficacy, indicated by statistically significant improvement, in these domains? How did the interventions work? Synthesis tools employed included the PEDro-P Scale, the TIDieR checklist and the ITAX. MAIN CONTRIBUTION: A total of 22 studies met the criteria for review. One study used solely language or communication interventions, but the remaining 21 studies used behavioural interventions which incorporated language and communication activities to varying degrees. Studies fell into four broad intervention types: reminiscence or life review; cognitive stimulation; narrative or storytelling; and multi-modality group communication. The majority of studies were of fair methodological quality, with a moderate level of detail provided in treatment reporting. Statistically significant improvement was reported by authors in all four intervention types and across language, communication and social domains. Social interaction, social support and behavioural skills were the most consistent mechanisms of action in the reviewed behavioural interventions. CONCLUSIONS & IMPLICATIONS: Despite limitations in the evidence base, there are important positive signs for the beneficial effects of supporting language and communication in care homes. Blinding of assessors, and the accuracy and accessibility of statistical reporting are important areas to address in order to improve the quality of the evidence base. WHAT THIS PAPER ADDS: Ageing can lead to reduced communication ability and activity, and in the care home setting there may also be fewer communication opportunities. This situation is likely to negatively impact well-being. Previous reviews have found evidence of the effectiveness of behavioural interventions in increasing well-being. The communication skills of older adults living in care homes is an underexplored topic. No systematic review to date has focused specifically on the evidence base for group language and communication interventions in this population. This review reveals important positive signs for the beneficial effects of supporting language and communication in care homes. Social interaction, social support, and behavioural skills were the most consistent mechanisms of action in the reviewed behavioural interventions.


Assuntos
Terapia Cognitivo-Comportamental , Idioma , Idoso , Terapia Comportamental , Comunicação , Humanos , Comunicação Interdisciplinar
6.
J Nat Prod ; 84(8): 2256-2264, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34314586

RESUMO

A new linear lipopeptide, phormidepistatin (1), containing an epi-statine amino acid was isolated from cf. Phormidium sp. strain UIC 10484. The planar structure was elucidated by 1D and 2D NMR experimentation. The relative configuration was determined by J-based configurational analysis and the absolute configuration by advanced Marfey's analysis. Given that the statine moiety is an established pharmacophore known to inhibit aspartic proteases, phormidepistatin was evaluated against cathepsin D and displayed limited activity. With 1 containing a statine-like moiety, we sought to assess the distribution of this γ-amino acid within the phylum Cyanobacteria. In-depth MS/MS analysis identified the presence of phormidepistatin in cf. Phormidium sp. UIC 10045 and cf. Trichormus sp. UIC 10039. A structure database search identified 33 known cyanobacterial metabolites containing a statine or statine-like amino acid and, along with phormidepistatin, were grouped into 10 distinct compound classes. A phylogenetic tree was built comprising all cyanobacteria with established 16S rRNA sequences known to produce statine or statine-like-containing compound classes. This analysis suggests the incorporation of the γ-amino acid into secondary metabolites is taxonomically widespread within the phylum. Overall, it is our assessment that cyanobacteria are a potential source for statine or statine-like-containing compounds.


Assuntos
Aminoácidos/química , Cianobactérias/química , Lipopeptídeos/química , Cianobactérias/classificação , Água Doce , Indiana , Estrutura Molecular , Phormidium , Filogenia , RNA Ribossômico 16S/genética
7.
FEBS Open Bio ; 11(3): 705-713, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33480189

RESUMO

Combinations of human lysozyme (hLYS) and antimicrobial peptides (AMPs) are known to exhibit either additive or synergistic activity, and as a result, they have therapeutic potential for persistent and antibiotic-resistant infections. We examined hLYS activity against Pseudomonas aeruginosa when combined with six different AMPs. In contrast to prior reports, we discovered that some therapeutically relevant AMPs manifest striking antagonistic interactions with hLYS across particular concentration ranges. We further found that the synthetic AMP Tet009 can inhibit hLYS-mediated bacterial lysis. To the best of our knowledge, these results represent the first observations of antagonism between hLYS and AMPs, and they advise that future development of lytic enzyme and AMP combination therapies considers the potential for antagonistic interactions.


Assuntos
Peptídeos Antimicrobianos/farmacologia , Muramidase/efeitos adversos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Peptídeos Antimicrobianos/química , Bacteriólise/efeitos dos fármacos , Antagonismo de Drogas , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos
8.
J Cardiovasc Electrophysiol ; 30(3): 348-356, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30575185

RESUMO

INTRODUCTION: Amiodarone reduces recurrent ventricular tachyarrhythmias (VTA) but may worsen cardiovascular outcomes in heart failure (HF) patients. Cardiac resynchronization therapy (CRT) may also be antiarrhythmic. When patients with prior sustained VTA are upgraded to CRT defibrillators (CRT-D) from conventional implantable cardioverter-defibrillators (ICDs), should concomitant amiodarone be continued or is CRT's antiarrhythmic potential sufficient? METHODS AND RESULTS: We identified 67 patients from a prospective CRT registry with spontaneous sustained VTA, New York Heart Association (NYHA) II-IV HF, and left bundle-branch block (LBBB) who were upgraded to CRT defibrillators from conventional ICDs. We compared changes in QRS duration and left ventricular ejection fraction (LVEF) pre- and post-CRT, time to death, transplant or ventricular assist device (VAD), and time to recurrent VTA therapies between 37 patients continuing amiodarone therapy and 30 amiodarone-naïve patients. Amiodarone-treated patients had worse renal function and a higher prevalence of prior VTA storm compared with amiodarone-naïve patients. After CRT, amiodarone-treated patients demonstrated less QRS narrowing (8 vs 20 ms; P = 0.021) and less LVEF improvement (-2.7 vs +5.2%; P = 0.006). Over 29 months, 31 (47%) patients died and 13 (20%) received transplant or VAD. Risk of death, transplant, or VAD was greater in amiodarone-treated than -naïve patients (corrected hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.12-4.11; P = 0.022). Appropriate CRT-D therapies occurred in 37 (55%) patients; amiodarone use was not associated time to first therapy (HR, 1.13; 95% CI, 0.59-2.16; P = 0.72). CONCLUSION: In patients with sustained VTA and LBBB upgraded from conventional ICDs to CRT defibrillators, concomitant amiodarone use is associated with less QRS narrowing, less LVEF improvement, greater risk of death, transplant, or VAD, and similar risk of recurrent VTA.


Assuntos
Amiodarona/efeitos adversos , Antiarrítmicos/efeitos adversos , Arritmias Cardíacas/terapia , Dispositivos de Terapia de Ressincronização Cardíaca , Terapia de Ressincronização Cardíaca , Desfibriladores Implantáveis , Cardioversão Elétrica/instrumentação , Insuficiência Cardíaca/terapia , Frequência Cardíaca/efeitos dos fármacos , Potenciais de Ação , Idoso , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/mortalidade , Arritmias Cardíacas/fisiopatologia , Terapia de Ressincronização Cardíaca/efeitos adversos , Terapia de Ressincronização Cardíaca/mortalidade , Bases de Dados Factuais , Cardioversão Elétrica/efeitos adversos , Cardioversão Elétrica/mortalidade , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
9.
Acad Med ; 91(2): 222, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26813652
10.
J Biol Chem ; 284(11): 6982-7, 2009 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-19098307

RESUMO

Spectrins are tetrameric actin-cross-linking proteins that form an elastic network, termed the membrane skeleton, on the cytoplasmic surface of cellular membranes. At the plasma membrane, the membrane skeleton provides essential support, preventing loss of membrane material to environmental shear stresses. The skeleton also controls the location, abundance, and activity of membrane proteins that are critical to cell and tissue function. The ability of the skeleton to modulate membrane stability and function requires adaptor proteins that bind the skeleton to membranes. The principal adaptors are the ankyrin proteins, which bind to the beta-subunit of spectrin and to the cytoplasmic domains of numerous integral membrane proteins. Here, we present the crystal structure of the ankyrin-binding domain of human beta2-spectrin at 1.95 A resolution together with mutagenesis data identifying the binding surface for ankyrins on beta2-spectrin.


Assuntos
Anquirinas/química , Espectrina/química , Substituição de Aminoácidos , Anquirinas/genética , Anquirinas/metabolismo , Sítios de Ligação/fisiologia , Membrana Celular/química , Membrana Celular/genética , Membrana Celular/metabolismo , Cristalografia por Raios X , Citoesqueleto/química , Citoesqueleto/genética , Citoesqueleto/metabolismo , Humanos , Mutação de Sentido Incorreto , Mapeamento de Peptídeos , Estrutura Terciária de Proteína/fisiologia , Espectrina/genética , Espectrina/metabolismo
11.
J Biol Chem ; 282(36): 26552-61, 2007 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-17620337

RESUMO

E-cadherin is a ubiquitous component of lateral membranes in epithelial tissues and is required to form the first lateral membrane domains in development. Here, we identify ankyrin-G as a molecular partner of E-cadherin and demonstrate that ankyrin-G and beta-2-spectrin are required for accumulation of E-cadherin at the lateral membrane in both epithelial cells and early embryos. Ankyrin-G binds to the cytoplasmic domain of E-cadherin at a conserved site distinct from that of beta-catenin. Ankyrin-G also recruits beta-2-spectrin to E-cadherin-beta-catenin complexes, thus providing a direct connection between E-cadherin and the spectrin/actin skeleton. In addition to restricting the membrane mobility of E-cadherin, ankyrin-G and beta-2-spectrin also are required for exit of E-cadherin from the trans-Golgi network in a microtubule-dependent pathway. Ankyrin-G and beta-2-spectrin co-localize with E-cadherin in preimplantation mouse embryos. Moreover, knockdown of either ankyrin-G or beta-2-spectrin in one cell of a two-cell embryo blocks accumulation of E-cadherin at sites of cell-cell contact. E-cadherin thus requires both ankyrin-G and beta-2-spectrin for its cellular localization in early embryos as well as cultured epithelial cells. We have recently reported that ankyrin-G and beta-2-spectrin collaborate in biogenesis of the lateral membrane ( Kizhatil, K., Yoon, W., Mohler, P. J., Davis, L. H., Hoffman, J. A., and Bennett, V. (2007) J. Biol. Chem. 282, 2029-2037 ). Together with the current findings, these data suggest a ankyrin/spectrin-based mechanism for coordinating membrane assembly with extracellular interactions of E-cadherin at sites of cell-cell contact.


Assuntos
Anquirinas/metabolismo , Blastômeros/metabolismo , Caderinas/metabolismo , Células Epiteliais/metabolismo , Junções Intercelulares/metabolismo , beta Catenina/metabolismo , Rede trans-Golgi/metabolismo , Actinas/metabolismo , Animais , Anquirinas/deficiência , Blastômeros/citologia , Proteínas de Transporte/metabolismo , Linhagem Celular , Células Epiteliais/citologia , Humanos , Junções Intercelulares/genética , Camundongos , Proteínas dos Microfilamentos/deficiência , Proteínas dos Microfilamentos/metabolismo , Microtúbulos/metabolismo , Ligação Proteica/fisiologia , Estrutura Terciária de Proteína/fisiologia , Transporte Proteico/fisiologia , Rede trans-Golgi/genética
12.
J Biol Chem ; 282(3): 2029-37, 2007 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-17074766

RESUMO

Ankyrins are a family of adapter proteins required for localization of membrane proteins to diverse specialized membrane domains including axon initial segments, specialized sites at the transverse tubule/sarcoplasmic reticulum in cardiomyocytes, and lateral membrane domains of epithelial cells. Little is currently known regarding the molecular basis for specific roles of different ankyrin isoforms. In this study, we systematically generated alanine mutants of clusters of charged residues in the spectrin-binding domains of both ankyrin-B and -G. The corresponding mutants were evaluated for activity in either restoration of abnormal localization of the inositol trisphosphate receptor in the sarcoplasmic reticulum in mutant mouse cardiomyocytes deficient in ankyrin-B or in prevention of loss of lateral membrane in human bronchial epithelial cells depleted of ankyrin-G by small interfering RNA. Interestingly, ankyrin-B and -G share two homologous sites that result in loss of function in both systems, suggesting that common molecular interactions underlie diverse roles of these isoforms. Ankyrins G and B also exhibit differences; mutations affecting spectrin binding had no effect on ankyrin-B function but did abolish activity of ankyrin-G in restoring lateral membrane biogenesis. Depletion of beta(2)-spectrin by small interfering RNA phenocopied depletion of ankyrin-G and resulted in a failure to form new lateral membrane in interphase and mitotic cells. These results demonstrate that ankyrin-G and beta(2)-spectrin are functional partners in biogenesis of the lateral membrane of epithelial cells.


Assuntos
Anquirinas/química , Brônquios/citologia , Células Epiteliais/citologia , Espectrina/química , Alanina/química , Sequência de Aminoácidos , Animais , Animais Recém-Nascidos , Anquirinas/metabolismo , Células Epiteliais/metabolismo , Humanos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Camundongos , Dados de Sequência Molecular , Miócitos Cardíacos/metabolismo , Ligação Proteica , Ratos
13.
J Biol Chem ; 279(24): 25798-804, 2004 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-15075330

RESUMO

Ankyrins-R, -B, and -G are a family of membrane-associated adaptors required for localization of structurally diverse proteins to specialized membrane domains, including axon initial segments, cardiomyocyte T-tubules, and epithelial cell lateral membranes. Ankyrins are often co-expressed in the same cells and, although structurally similar, have non-overlapping functions. We previously determined that the regulatory domain of ankyrin-B defines specificity between ankyrins B and G in cardiomyocytes. Here, we identify key residues on the surface of an amphipathic alpha-helix unique to the regulatory domain of ankyrin-B that are essential for the function of ankyrin-B in cardiomyocytes. Using circular dichroism, we determined that a peptide representing the predicted helix folds as a helix in solution. Alanine-scanning mutagenesis revealed that residues 1773, 1777, 1780, 1784, and 1788 located in a patch on one surface the helix are critical for ankyrin-B function in cardiomyocytes. In a parallel set of experiments we determined that the molecular co-chaperone human DnaJ homologue 1 (Hdj1)/Hsp40 interacts with the ankyrin-B regulatory domain. Moreover, interaction of Hdj1/Hsp40 with the regulatory domain was mapped by random mutagenesis to same surface of the alpha-helix that is required for ankyrin-B function. These results provide new insight into the molecular basis for specificity between ankyrin-based pathways by defining a key alpha-helix structure in the divergent regulatory domain of ankyrin-B as well as interaction of the helix with Hdj1/Hsp40, the first downstream target for ankyrin-B-specific function.


Assuntos
Anquirinas/química , Proteínas de Choque Térmico/química , Sequência de Aminoácidos , Animais , Anquirinas/fisiologia , Proteínas de Choque Térmico HSP40 , Humanos , Camundongos , Dados de Sequência Molecular , Miócitos Cardíacos/fisiologia , Isoformas de Proteínas , Estrutura Secundária de Proteína
14.
J Biol Chem ; 279(13): 12980-7, 2004 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-14722080

RESUMO

The molecular mechanisms required for inositol 1,4,5-trisphosphate receptor (InsP(3)R) targeting to specialized endoplasmic reticulum membrane domains are unknown. We report here a direct, high affinity interaction between InsP(3)R and ankyrin-B and demonstrate that this association is critical for InsP(3)R post-translational stability and localization in cultures of neonatal cardiomyocytes. Recombinant ankyrin-B membrane-binding domain directly interacts with purified cerebellar InsP(3)R (K(d) = 2 nm). 220-kDa ankyrin-B co-immunoprecipitates with InsP(3)R in tissue extracts from brain, heart, and lung. Alanine-scanning mutagenesis of the ankyrin-B ANK (ankyrin repeat) repeat beta-hairpin loop tips revealed that consecutive ANK repeat beta-hairpin loop tips (repeats 22-24) are required for InsP(3)R interaction, thus providing the first detailed evidence of how ankyrin polypeptides associate with membrane proteins. Pulse-chase biosynthesis experiments demonstrate that reduction or loss of ankyrin-B in ankyrin-B (+/-) or ankyrin-B (-/-) neonatal cardiomyocytes leads to approximately 3-fold reduction in half-life of newly synthesized InsP(3)R. Furthermore, interactions with ankyrin-B are required for InsP(3)R stability as abnormal InsP(3)R phenotypes, including mis-localization, and reduced half-life in ankyrin-B (+/-) cardiomyocytes can be rescued by green fluorescent protein (GFP)-220-kDa ankyrin-B but not by GFP-220-kDa ankyrin-B mutants, which do not associate with InsP(3)R. These new results provide the first physiological evidence of a molecular partner required for early post-translational stability of InsP(3)R.


Assuntos
Anquirinas/metabolismo , Canais de Cálcio/biossíntese , Miócitos Cardíacos/citologia , Receptores Citoplasmáticos e Nucleares/biossíntese , Animais , Animais Recém-Nascidos , Encéfalo/embriologia , Bovinos , Linhagem Celular , Membrana Celular/metabolismo , Relação Dose-Resposta a Droga , Retículo Endoplasmático/metabolismo , Proteínas de Fluorescência Verde , Humanos , Receptores de Inositol 1,4,5-Trifosfato , Cinética , Proteínas Luminescentes/metabolismo , Camundongos , Microscopia de Fluorescência , Modelos Moleculares , Mutagênese , Mutação , Fenótipo , Testes de Precipitina , Ligação Proteica , Processamento de Proteína Pós-Traducional , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Fatores de Tempo , Distribuição Tecidual
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