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1.
Anaesthesist ; 69(11): 803-809, 2020 Nov.
Article in German | MEDLINE | ID: mdl-32930805

ABSTRACT

BACKGROUND: Criteria for the identification of suitable applicants for undergraduate and postgraduate medical education are greatly and ubiquitously discussed. Apart from the acquisition of theoretical knowledge and practical skills, certain personality traits are necessary for practicing the medical profession; however, little is known on the personality traits required for medical subspecialties. This study had two objectives: 1) identification and evaluation of personality traits which are essential for performing anesthesiology and 2) establishment of a job specification for anesthesiology. METHODS: We performed a survey among German anesthesiologists using an online questionnaire. This questionnaire collected demographic data, such as age, gender, level of postgraduate education and 28 personality traits from 5 categories: cognition, psychomotor, physical, sensory and social interactive properties. The participants were asked to rate the personality traits on a 5-point Likert scale. Statistical analysis was performed using an ANOVA. RESULTS: A total of 714 questionnaires were analyzed. Social interactive skills and cognitive personality traits were considered as most important for a clinical career in anesthesiology. The three personality traits rated highest were a high decision-making ability, stress tolerance and speed of perception. Furthermore, a high apprehension, affability and patient-oriented behavior are needed. CONCLUSION: A job specification describing important personality traits can be useful to advise both undergraduates and postgraduates on their medical career and for medical team simulation tasks. For the clinical practice in anesthesiology, for example, high social interactive and cognitive personality traits are required.


Subject(s)
Anesthesiology , Anesthesiologists , Anxiety , Humans , Personality , Surveys and Questionnaires
2.
Med Teach ; 40(11): 1091-1101, 2018 11.
Article in English | MEDLINE | ID: mdl-30251906

ABSTRACT

Selection and recruitment into healthcare education and practice is a key area of interest for educators with significant developments in research, policy, and practice in recent years. This updated consensus statement, developed through a multi-stage process, examines future opportunities and challenges in selection and recruitment. There is both a gap in the literature around and a compelling case for further theoretical and empirical literature to underpin the development of overall selection philosophes and policies and their enactment. More consistent evidence has emerged regarding the quality of different selection methods. Approaches to selection are context-dependent, requiring the consideration of an institution's philosophy regarding what they are trying to achieve, the communities it purports to serve, along with the system within which they are used. Diversity and globalization issues continue to be critically important topics. Further research is required to explore differential attainment and explain why there are substantial differences in culturally acceptable ways of approaching diversity and widening access. More sophisticated evaluation approaches using multi-disciplinary theoretical frameworks are required to address the issues. Following a discussion of these areas, 10 recommendations are presented to guide future research and practice and to encourage debate between colleagues across the globe.


Subject(s)
Health Personnel/education , Personnel Selection/organization & administration , Consensus , Cultural Diversity , Humans , Personnel Selection/standards , Policy , School Admission Criteria
3.
Article in German | MEDLINE | ID: mdl-19626281

ABSTRACT

Since 2005, German universities are free to select 60% of their freshmen according to their own admission processes. In 2008, selection of medical students in Germany was mainly based on grades achieved in final school examinations (Abiturnote). Further criteria were used in various combinations: some medical schools conducted interviews or tests, while others rewarded work experience, research awards, or cultural and social dedication. However, solely high school grades and some measures of ability show acceptable validity coefficients with regard to academic and professional success. Evidence for the prognostic validity of interviews and other noncognitive criteria cannot be regarded as sufficient. Recent studies conducted in Hamburg and Heidelberg attempt to validate selection criteria such as a test of natural sciences, final school examination grades, work experience, and voluntary work in the social sector. For the selection of medical students, we recommend the use of final school examination grades in combination with special written test results or, in the case of dentistry, a test of manual dexterity. Interviews might be beneficial to emphasize the importance of non-academic skills and to strengthen the ties of students to their faculty.


Subject(s)
Aptitude , Education, Dental , Education, Medical , School Admission Criteria , Achievement , Career Choice , Educational Measurement , Germany , Humans , Interviews as Topic
4.
J Cell Sci ; 114(Pt 20): 3599-606, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11707512

ABSTRACT

The neuropeptide head activator stimulates cell proliferation of neuronal precursor and neuroendocrine cells. The mitogenic signaling cascade requires Ca(2+) influx for which, as we show in this paper, the growth-factor-regulated Ca(2+)-permeable cation channel, GRC, is responsible. GRC is a member of the transient receptor potential channel family. In uninduced cells only low amounts of GRC are present on the plasma membrane but, upon stimulation with head activator, GRC translocates from an intracellular compartment to the cell surface. Head activator functions as an inducer of GRC translocation in neuronal and neuroendocrine cells, which express GRC endogenously, and also in COS-7 cells after transfection with GRC. Head activator is no direct ligand for GRC, but its action requires the presence of a receptor coupled to a pertussis-toxin inhibitable G-protein. Heterologously expressed GRC becomes activated by head activator, which results in opening of the channel and Ca(2+) influx. SK&F 96365, an inhibitor specific for TRP-like channels, blocks Ca(2+) entry and, consequently, translocation of GRC is prevented. Head activator-induced GRC activation and translocation are also inhibited by wortmannin and KN-93, blockers of the phosphatidylinositol 3-kinase and of the Ca(2+)/calmodulin-dependent kinase, respectively, which implies a role for both kinases in head-activator signaling to GRC.


Subject(s)
Calcium Channels/metabolism , Calcium/metabolism , Neurons/drug effects , Neuropeptides/pharmacology , Signal Transduction , Androstadienes/pharmacology , Animals , Benzylamines/pharmacology , CHO Cells , COS Cells , Calcium Channel Blockers/pharmacology , Calcium Channels/genetics , Cell Membrane , Cricetinae , Enzyme Inhibitors/pharmacology , Humans , Imidazoles/pharmacology , Microscopy, Fluorescence , Models, Biological , Neurons/cytology , Neurons/physiology , Patch-Clamp Techniques , Pertussis Toxin , Protein Transport , Purines/pharmacology , Pyrrolidonecarboxylic Acid/analogs & derivatives , Recombinant Fusion Proteins/metabolism , Roscovitine , Sulfonamides/pharmacology , TRPV Cation Channels , Virulence Factors, Bordetella/pharmacology , Wortmannin
5.
Hum Genet ; 108(6): 529-36, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11499680

ABSTRACT

The two human proteins with a VPS10 domain, SorLA and sortilin, both bind neuropeptides. Searching for other VPS10-domain proteins in the database revealed three new putative human neuropeptide receptors. The new receptors were designated SorCS1, SorCS2 and SorCS3, due to their identical domain composition, which, except for the N-terminal VPS10 domain, differs from that of SorLA and sortilin. Using the databases of the human genome project we elucidated the exon-intron structures of the human VPS10-receptor genes. They contain many short exons, separated by introns, several of which extend over more than 50 kb. The three SorCS genes encompass more than 500 kb of genomic DNA and therefore represent some of the largest known human genes. All these genes map to chromosomal localisations of known genetic diseases, many of them neurological disorders, corresponding to the strong expression of these receptors in the brain. CpG islands are located in the first exon of each of the VPS10-receptor genes and might be involved in developmental or tissue-specific regulation of gene expression.


Subject(s)
Exons/genetics , Receptors, Neuropeptide/genetics , Amino Acid Sequence , Binding Sites , Blotting, Northern , Chromosome Mapping , CpG Islands/genetics , DNA, Complementary/chemistry , DNA, Complementary/genetics , Evolution, Molecular , Genes/genetics , Molecular Sequence Data , Phylogeny , Protein Isoforms/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Tissue Distribution
6.
Mech Dev ; 100(2): 335-8, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11165493

ABSTRACT

We report the identification of a fourth member of the VPS10 domain containing receptor family, SorCS2, highly expressed in the developing and mature murine central nervous system. During early central nervous system development its main site of expression is the floor plate. In addition, high transcript levels were detected transiently in a variety of brain regions including the dopaminergic midbrain nuclei and the dorsal thalamus. Outside the nervous system expression is detected in lung and heart and transiently in a variety of mesodermally derived tissues.


Subject(s)
Fungal Proteins/biosynthesis , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/genetics , Receptors, Cell Surface/biosynthesis , Receptors, Cell Surface/genetics , Saccharomyces cerevisiae Proteins , Vesicular Transport Proteins , Amino Acid Sequence , Animals , Blotting, Northern , Central Nervous System/embryology , Central Nervous System/metabolism , Cloning, Molecular , DNA, Complementary/metabolism , Heart/embryology , In Situ Hybridization , Lung/embryology , Mesencephalon/embryology , Mice , Molecular Sequence Data , Neurons/metabolism , Protein Structure, Tertiary , Tissue Distribution
7.
J Cell Sci ; 113 Pt 24: 4475-85, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11082041

ABSTRACT

The single transmembrane receptor SorLA is the mammalian orthologue of the head activator-binding protein, HAB, from hydra. The human neuronal precursor cell line NT2 and the neuroendocrine cell line BON produce head activator (HA) and respond to HA by entry into mitosis and cell proliferation. They express SorLA, and bind HA with nanomolar affinity. HA coupled to Sepharose is able to precipitate SorLA specifically proving that SorLA binds HA. Using antisera directed against extra- and intracellular epitopes we find SorLA as membrane receptor and as soluble protein released from cells into the culture medium. Cell lines differ strongly in processing of SorLA, with NT2 cells expressing SorLA mainly as membrane receptor, whereas release predominates in BON cells. Soluble SorLA lacks the intracellular domain and is shed from the transmembrane protein by a metalloprotease. Release from cells and brain slices is stimulated by HA and by phorbol ester, and it is blocked by a metalloprotease inhibitor and by lowering the temperature to 20 degrees C. Blockade of SorLA shedding and treatment of cells with SorLA antisense oligonucleotides lead to a decrease in the rate of cell proliferation. From this we conclude that SorLA is necessary to mediate the mitogenic effect of endogenous HA. HA enhances the translocation of SorLA from internal membranes to the cell surface and its internalization. In addition, HA stimulates SorLA synthesis hinting at an autocatalytic feedback loop in which the ligand activates production, processing, and translocation of its receptor.


Subject(s)
Membrane Transport Proteins , Nerve Tissue Proteins/metabolism , Neuropeptides/metabolism , Receptors, LDL/metabolism , Animals , Brain/metabolism , Brain/pathology , Cell Line , Cell Membrane/metabolism , Furin , Humans , LDL-Receptor Related Proteins , Ligands , Metalloendopeptidases/metabolism , Mice , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/genetics , Protein Processing, Post-Translational , Pyrrolidonecarboxylic Acid/analogs & derivatives , Receptors, LDL/biosynthesis , Receptors, LDL/genetics , Solubility , Subtilisins/metabolism
8.
J Biotechnol ; 77(2-3): 219-34, 2000 Feb 17.
Article in English | MEDLINE | ID: mdl-10682281

ABSTRACT

The hydrophobic human beta 2 adrenergic receptor was produced in fusion to the hydrophilic maltose-binding protein (MalE) in Escherichia coli. Photoaffinity labeling with the adrenergic ligand [125I]cyanopindolole-diazirine indicated that the majority of the protein was proteolyzed in the intergenic region between the fusion partners after production in E. coli. The simple and fast genetics of the bacterium enabled us to engineer a linker with an increased proteolytic stability. The fusion protein produced in E. coli was fully functional with respect to binding of adrenergic ligands and coupling to stimulatory GTP-binding protein. The production level with 3 pmol receptor fusion protein per mg membrane protein in a crude membrane preparation was significantly higher than those reported for other beta 2 adrenergic receptor constructs in E. coli. After solubilization with dodecanoyl sucrose, the fusion protein was purified to near homogeneity by affinity chromatography on immobilized Ni2+ ions (binding to a C-terminal His6-tag) and on crosslinked amylose (binding to the MalE). In order to achieve higher production levels, the fusion protein preceded by an insect signal peptide was produced in baculovirus-infected insect cells. As expected, the production level with about 17 pmol receptor per mg membrane protein was higher in the insect cells than in E. coli. The receptor fusion protein produced in the insect cells bound adrenergic ligands and activated heterotrimeric GTP-binding proteins with biochemical properties comparable to that of the unfused receptor.


Subject(s)
ATP-Binding Cassette Transporters , Baculoviridae/genetics , Carrier Proteins/genetics , Escherichia coli Proteins , Escherichia coli/genetics , Genetic Engineering , Monosaccharide Transport Proteins , Periplasmic Binding Proteins , Receptors, Adrenergic, beta/genetics , Recombinant Fusion Proteins , Spodoptera/metabolism , Adrenergic beta-Antagonists , Animals , Chromatography, Affinity , Diazomethane , GTP-Binding Proteins/metabolism , Humans , Maltose-Binding Proteins , Photoaffinity Labels , Pindolol/analogs & derivatives , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/isolation & purification , Transfection
9.
Eur J Cell Biol ; 79(11): 810-5, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11139144

ABSTRACT

CDC25 phosphatases play key roles in cell proliferation by activating cell cycle-specific cyclin-dependent kinases (CDKs). We identified four new splice variants in the amino-terminal regulatory region of human cdc25C and one in cdc25A. All variants except one retain an intact catalytic domain. Alternative splicing results in loss of phosphorylation sites for kinases like CDK and the calcium/calmodulin-dependent kinase II (CaMKII), which influence CDC25 activity and compartmental localization. In NT2 teratocarcinoma cells, induced for nerve cell differentiation, the smaller sized variant of cdc25C was upregulated. At the protein level both phosphorylation state and isoform distribution differed between cell lines and cell cycle phases.


Subject(s)
Alternative Splicing/genetics , Cell Cycle Proteins/genetics , Regulatory Sequences, Nucleic Acid/genetics , cdc25 Phosphatases/genetics , Amino Acid Sequence , Base Sequence , Blotting, Western , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/metabolism , Humans , Molecular Sequence Data , Protein Isoforms , Reverse Transcriptase Polymerase Chain Reaction , Sequence Alignment , Tumor Cells, Cultured , cdc25 Phosphatases/chemistry , cdc25 Phosphatases/metabolism
10.
Biochem Biophys Res Commun ; 266(2): 347-51, 1999 Dec 20.
Article in English | MEDLINE | ID: mdl-10600506

ABSTRACT

A novel receptor, SorCS, was isolated from murine brain. It shows homology to the mosaic receptor SorLA and the neurotensin receptor sortilin based on a common VPS10 domain which is the hallmark of this new receptor family. In the N-terminus of SorCS two putative cleavage sites for the convertase furin mark the beginning of the VPS10 domain, followed by a module of imperfect leucine-rich repeats and a transmembrane domain. The short intracellular C-terminus contains consensus signals for rapid internalization. The identified putative binding motifs for SH2 and SH3 domains are unique in the family of VPS10 domain receptors. SorCS is predominantly expressed in brain, but also in heart, liver, and kidney. SorCS transcripts detected by in situ hybridization in the murine central nervous system point to a neuronal expression.


Subject(s)
Membrane Transport Proteins , Nerve Tissue Proteins/genetics , Receptors, Cell Surface/genetics , Receptors, LDL , Saccharomyces cerevisiae Proteins , Vesicular Transport Proteins , Adaptor Proteins, Vesicular Transport , Amino Acid Sequence , Animals , Brain/metabolism , Cloning, Molecular , Fungal Proteins/chemistry , In Situ Hybridization , Membrane Glycoproteins/chemistry , Mice , Molecular Sequence Data , Nerve Tissue Proteins/chemistry , RNA, Messenger/metabolism , Receptors, Cell Surface/chemistry , Sequence Alignment , Sequence Homology, Amino Acid
11.
Development ; 126(18): 4077-86, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10457016

ABSTRACT

The neuropeptide head activator plays an important role for proliferation and determination of stem cells in hydra. By affinity chromatography a 200 kDa head-activator binding protein, HAB, was isolated from the multiheaded mutant of Chlorohydra viridissima. Partial amino acid sequences were used to clone the HAB cDNA which coded for a receptor with a unique alignment of extracellular modules, a transmembrane domain, and a short carboxy-terminal cytoplasmic tail. A mammalian HAB homologue with identical alignment of these modules is expressed early in brain development. Specific antibodies revealed the presence of HAB in hydra as a transmembrane receptor, but also as secreted protein, both capable of binding head activator. Secretion of HAB during regeneration and expression in regions of high determination potential hint at a role for HAB in regulating the concentration and range of action of head activator.


Subject(s)
Hydra/physiology , Neuropeptides/metabolism , Receptors, Peptide/metabolism , Amino Acid Sequence , Animals , Cloning, Molecular , Ectoderm , Embryo, Nonmammalian , Gene Expression Regulation, Developmental , Hydra/embryology , In Situ Hybridization , Membrane Proteins/genetics , Membrane Proteins/metabolism , Molecular Sequence Data , Mutation , Pyrrolidonecarboxylic Acid/analogs & derivatives , Regeneration , Sequence Homology, Amino Acid , Solubility
13.
Mech Dev ; 70(1-2): 65-76, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9510025

ABSTRACT

Recently, a new type of transmembrane protein with a unique combination of protein domains was characterized from human, rabbit and chicken. This protein exhibits features of the low-density lipoprotein receptor family and shows homology to the receptor of the neuropeptide head activator isolated from hydra. To study the temporal and spatial pattern of expression of this unusual new receptor we have isolated a murine homolog and, in accordance with its human counterpart, named it mSorLA. Northern blot analysis revealed the highest abundance of mSorLA transcripts in the adult brain, lower levels in a variety of other organs and expression during embryogenesis. In situ hybridization showed predominant localization in neurons of the cortex, the hippocampus and the cerebellum. During embryonic development mSorLA displayed a unique pattern of expression in the cerebral cortex, where a subpopulation of neurons was labeled before final differentiation. Transcripts of mSorLA were also detected outside the central nervous system in regions active in morphogenesis.


Subject(s)
Cerebral Cortex/embryology , Cerebral Cortex/metabolism , Receptors, LDL/genetics , Animals , Cerebral Cortex/growth & development , Chickens , Cloning, Molecular , DNA, Complementary/genetics , Gene Expression Regulation, Developmental , Humans , In Situ Hybridization , Mice , Mosaicism , Rabbits
14.
Eur J Biochem ; 244(3): 940-5, 1997 Mar 15.
Article in English | MEDLINE | ID: mdl-9108269

ABSTRACT

Head activator (HA) is a neuropeptide conserved from hydra to humans. It acts in the development of neuronal cells and is, in hydra, an important factor in head regeneration. Here we report the solubilization and purification of one head activator receptor (Kd approximately 1 nM) from a multiheaded mutant of Chlorohydra viridissima using HA affinity chromatography. Functional solubilization of the HA receptor from hydra membranes was best performed with Triton X-100 or Chaps. The addition of salt or urea and the protein concentration were important parameters in determining the yield of solubilized receptor. For affinity chromatography HA was coupled to Sepharose. The length of the spacer was optimized with respect to binding of the solubilized HA receptor. After rigorous washing a 200-kDa protein was eluted from HA Sepharose but not from control Sepharoses coupled to bradykinin or without peptide. Ligand binding was preserved in the eluate from the HA Sepharose, and a 200-kDa protein could be photoaffinity labeled. The 200-kDa protein was shown to be glycosylated mainly of the N-linked type. By Edman degradation of the purified protein sequence information was obtained for the N-terminus and after protease digestion for several internal peptides.


Subject(s)
Hydra/metabolism , Neuropeptides/metabolism , Receptors, Peptide/isolation & purification , Amino Acid Sequence , Animals , Chromatography, Affinity , Glycosylation , Humans , Hydra/genetics , Molecular Sequence Data , Molecular Weight , Mutation , Neuropeptides/chemistry , Neuropeptides/genetics , Peptide Fragments/genetics , Peptide Fragments/isolation & purification , Pyrrolidonecarboxylic Acid/analogs & derivatives , Receptors, Peptide/genetics , Receptors, Peptide/metabolism , Solubility
15.
Eur J Biochem ; 235(3): 814-20, 1996 Feb 01.
Article in English | MEDLINE | ID: mdl-8654433

ABSTRACT

A photoaffinity ligand for the head-activator (HA) receptor from hydra was synthesized using solid-phase peptide synthesis and coupling of two HA peptides over their epsilon-amino groups of Lys7 with succinimidyl esters. The new ligand, Bpa-HA-HA bipeptide, contains one normal HA peptide and another where p-benzoylphenylalanine (Bpa) was added at the amino terminus to allow ultraviolet activation and Tyr11 instead of Phe11 for radioiodination. The 125I-Bpa-HA-HA bipeptide bound with nanomolar affinity to the HA receptor from the multiheaded mutant of Chlorohydra viridissima as measured in a filter assay. After photoaffinity labeling of the hydra membrane fraction, a 200-kDa band was detected using reducing or non-reducing SDS/PAGE and autoradiography. Unlabeled HA derivatives, but no other neuropeptides, inhibited the labeling. Competition experiments with HA-HA homobipeptide in the nanomolar range indicate that predominantly the low-affinity and not the high-affinity HA receptor was photolabeled. Further evidence that the labeled molecule is the HA receptor comes from specific photoaffinity labeling with a second ultraviolet-activatable ligand containing p-nitrophenylalanine. The HA receptor could be functionally solubilized with Triton X-100 or Chaps. In the solubilizate the 200-kDa HA receptor was photolabeled specifically by both ligands. Liquid-phase isoelectric focussing of the solubilizate indicated a pI of about 5.4 of the photolabeled molecule. After chemical deglycosylation with trifluoromethanesulfonic acid, the apparent molecular mass of the labeled molecule was decreased to 180 kDa, indicating that the receptor is glycosylated.


Subject(s)
Hydra/metabolism , Receptors, Peptide/chemistry , Affinity Labels , Amino Acid Sequence , Animals , Glycosylation , Isoelectric Focusing , Molecular Sequence Data , Neuropeptides/metabolism , Photochemistry , Pyrrolidonecarboxylic Acid/analogs & derivatives , Radioligand Assay , Receptors, Peptide/metabolism
16.
Eur J Biochem ; 213(2): 797-804, 1993 Apr 15.
Article in English | MEDLINE | ID: mdl-8386637

ABSTRACT

Spodoptera frugiperda insect cells (Sf9) containing the stably integrated human beta 2-adrenergic receptor gene under the control of the baculovirus IE1 promoter expressed up to 350,000 human receptors/cell. The number of receptors did not change with cell density or age of culture. The adrenergic receptors overexpressed in the insect cells were functional with respect to their ligand binding and signalling properties. Coupling of the receptors to endogenous GTP-binding proteins is demonstrated by hormone-dependent stimulation of GTPase and adenylyl cyclase activity in the transformed insect cells. Western-blot analysis revealed that the endogenous GTP-binding protein appears to be of the heterotrimeric type. Antibodies raised against the mammalian alpha subunit of stimulatory GTP-binding proteins cross-react with the insect alpha subunit of GTP-binding proteins, which also exhibits the same apparent molecular mass as its mammalian counterpart. The beta subunit of GTP-binding proteins from insect cells reacts with anti-peptide serum directed against the C-terminal amino acids of the mammalian beta subunit of GTP-binding proteins, but is about approximately 2 kDa larger than that of the beta subunit of GTP-binding proteins from bovine brain. Exposure of the transformed insect cells to L-isoproterenol rapidly induces uncoupling and internalization of 30% of the heterologously expressed receptors. In contrast to the situation in mammalian cells, prolonged exposure of the agonist (24 h) does not result in down regulation of the remaining 70% of the receptors.


Subject(s)
Adenylyl Cyclases/metabolism , GTP Phosphohydrolases/metabolism , GTP-Binding Proteins/metabolism , Receptors, Adrenergic, beta/physiology , Transfection , Animals , Base Sequence , Cell Line , Cell Membrane/metabolism , Cloning, Molecular , Down-Regulation , Escherichia coli/genetics , Humans , Isoproterenol/pharmacology , Kinetics , Ligands , Macromolecular Substances , Molecular Sequence Data , Moths , Oligodeoxyribonucleotides , Polymerase Chain Reaction/methods , Receptors, Adrenergic, beta/drug effects , Receptors, Adrenergic, beta/genetics , Recombinant Proteins/drug effects , Recombinant Proteins/metabolism , Restriction Mapping
17.
FEBS Lett ; 282(2): 441-4, 1991 May 06.
Article in English | MEDLINE | ID: mdl-1645288

ABSTRACT

A human cDNA fragment bearing the complete coding region for the beta 2-adrenergic receptor was introduced into the genome of Autographa california nuclear polyhedrosis virus under the control of the polyhedrin promoter. Binding studies using [125I]iodocyanopindolol showed that Sf9 insect cells infected with the recombinant virus expressed approximately 1 x 10(6) beta 2-adrenergic receptors on their cell surface. Photoaffinity labeling of whole cells and membranes revealed a molecular weight of approximately 46,000 for the expressed receptor. The receptor produced in insect cells is glycosylated but the extent and pattern differ from that of the receptor from human tissue. The heterologously expressed receptor was purified by alprenolol affinity chromatography, and was able to activate isolated Gs-protein.


Subject(s)
Receptors, Adrenergic, beta/isolation & purification , Recombinant Proteins/isolation & purification , Adenylyl Cyclases/metabolism , Alprenolol/metabolism , Baculoviridae , Cloning, Molecular , GTP-Binding Proteins/metabolism , Genetic Vectors , Glycosylation , Humans , In Vitro Techniques , Macromolecular Substances , Receptors, Adrenergic, beta/chemistry , Receptors, Adrenergic, beta/metabolism
18.
FEBS Lett ; 271(1-2): 62-6, 1990 Oct 01.
Article in English | MEDLINE | ID: mdl-2146154

ABSTRACT

Using the 'fusogen' polyethyleneglycol (PEG), Dawson et al. have concluded that both guanosine triphosphate (GTP)-induced calcium efflux and the enhancement of IP3-promoted calcium release from rat liver microsomal vesicles could be attributed to a GTP-dependent vesicle fusion. We have studied GTP-induced fusion of microsomal vesicles from rat exocrine pancreas using light scatter and fluorescence dequenching methods. In the presence of PEG (3%), GTP (10 microM) induced a decrease in light scatter and an increase in fluorescence in the fluorescence dequenching assay (GTP-effect) indicating fusion of the vesicles. Guanosine 5'-O-(3-thiotriphosphate) (10 microM) had no effect on its own and inhibited the GTP-induced signals. Preincubation of the vesicles with adenosine triphosphate (ATP) (4 mM) increased the GTP-effect by 80%, whereas bafilomycin B1, a specific inhibitor of vacuolar type H(+)-ATPases, and the protonophore CCCP (10 microM) inhibited only the ATP-dependent part of the GTP-effect. Inhibitors of the vacuolar type H(+)-ATPase, which are also SH-alkylating reagents such as N-ethylmaleimid (100 microM) and the tyrosine-, cysteine- and lysine-reactive reagent 7-chloro-4-nitrobenz-2-exa-1,3-diazole (10 microM), abolished the GTP-effect in the absence or presence of ATP. We conclude that GTP induces fusion of pancreatic microsomes which is increased by an H+ gradient established by a vacuolar type H(+)-ATPase.


Subject(s)
Cell Fusion/drug effects , Guanosine Triphosphate/pharmacology , Microsomes/physiology , Pancreas/physiology , Acridine Orange , Adenosine Triphosphatases/metabolism , Animals , Biological Transport , Fluorescence , Hydrogen/metabolism , Hydrogen-Ion Concentration , Microsomes/drug effects , Microsomes/enzymology , Models, Biological , Pancreas/drug effects , Pancreas/enzymology , Rats
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