Expression and Characterization of MICU2, a Ca2+ Sensor Protein

2019 ◽  
pp. 261-273 ◽  
Author(s):  
Wenping Wu ◽  
Jimin Zheng ◽  
Zongchao Jia
Keyword(s):  
Sensor Protein

scholarly journals Hemodynamic characterization of a transgenic rat strain stably expressing the calcium sensor protein GCaMP2

2019 ◽  
Vol 316 (5) ◽  
pp. H1224-H1228 ◽  
Author(s):  
Attila Oláh ◽  
Mihály Ruppert ◽  
Tamás István Orbán ◽  
Ágota Apáti ◽  
Balázs Sarkadi ◽  
...  
Keyword(s):  
Systolic Function ◽  
Left Ventricular ◽  
Heart Weight ◽  
Transgenic Rat ◽  
Calcium Sensor ◽  
Transgenic Rats ◽  
Sensor Protein ◽  
Rat Strain

A novel transgenic rat strain has recently been generated that stably expresses the genetically engineered calcium sensor protein GCaMP2 in different cell types, including cardiomyocytes, to investigate calcium homeostasis. To investigate whether the expression of the GCaMP2 protein itself affects cardiac function, in the present work we aimed at characterizing in vivo hemodynamics in the GCaMP2 transgenic rat strain. GCaMP2 transgenic rats and age-matched Sprague-Dawley control animals were investigated. In vivo hemodynamic characterization was performed by left ventricular (LV) pressure-volume analysis. Postmortem heart weight data showed cardiac hypertrophy in the GCaMP2 group (heart-weight-to-tibial-length ratio: 0.26 ± 0.01 GCaMP2 vs. 0.23 ± 0.01 g/cm Co, P < 0.05). We detected elevated mean arterial pressure and increased total peripheral resistance in transgenic rats. GCaMP2 transgenesis was associated with prolonged contraction and relaxation. LV systolic function was not altered in transgenic rats, as indicated by conventional parameters and load-independent, sensitive indices. We found a marked deterioration of LV active relaxation in GCaMP2 animals (τ: 16.8 ± 0.7 GCaMP2 vs. 12.2 ± 0.3 ms Co, P < 0.001). Our data indicated myocardial hypertrophy, arterial hypertension, and impaired LV active relaxation along with unchanged systolic performance in the heart of transgenic rats expressing the GCaMP2 fluorescent calcium sensor protein. Special caution should be taken when using transgenic models in cardiovascular studies. NEW & NOTEWORTHY Genetically encoded Ca2+-sensors, like GCaMP2, are important tools to reveal molecular mechanisms for Ca2+-sensing. We provided left ventricular hemodynamic characterization of GCaMP2 transgenic rats and found increased afterload, cardiac hypertrophy, and prolonged left ventricular relaxation, along with unaltered systolic function and contractility. Special caution should be taken when using this rodent model in cardiovascular pharmacological and toxicological studies.

scholarly journals Mutagenesis and Functional Characterization of the Four Domains of GlnD, a Bifunctional Nitrogen Sensor Protein

2010 ◽  
Vol 192 (11) ◽  
pp. 2711-2721 ◽  
Author(s):  
Yaoping Zhang ◽  
Edward L. Pohlmann ◽  
Jose Serate ◽  
Mary C. Conrad ◽  
Gary P. Roberts
Keyword(s):  
Escherichia Coli ◽  
Functional Analysis ◽  
Nitrogen Assimilation ◽  
Rhodospirillum Rubrum ◽  
Functional Characterization ◽  
Enteric Bacteria ◽  
Truncated Protein ◽  
Primary Sensor ◽  
Sensor Protein

ABSTRACT GlnD is a bifunctional uridylyltransferase/uridylyl-removing enzyme (UTase/UR) and is believed to be the primary sensor of nitrogen status in the cell by sensing the level of glutamine in enteric bacteria. It plays an important role in nitrogen assimilation and metabolism by reversibly regulating the modification of PII protein; PII in turn regulates a variety of other proteins. GlnD appears to have four distinct domains: an N-terminal nucleotidyltransferase (NT) domain; a central HD domain, named after conserved histidine and aspartate residues; and two C-terminal ACT domains, named after three of the allosterically regulated enzymes in which this domain is found. Here we report the functional analysis of these domains of GlnD from Escherichia coli and Rhodospirillum rubrum. We confirm the assignment of UTase activity to the NT domain and show that the UR activity is a property specifically of the HD domain: substitutions in this domain eliminated UR activity, and a truncated protein lacking the NT domain displayed UR activity. The deletion of C-terminal ACT domains had little effect on UR activity itself but eliminated the ability of glutamine to stimulate that activity, suggesting a role for glutamine sensing by these domains. The deletion of C-terminal ACT domains also dramatically decreased UTase activity under all conditions tested, but some of these effects are due to the competition of UTase activity with unregulated UR activity in these variants.

scholarly journals Characterization of the Bacterial Sensor Protein PhoQ

1997 ◽  
Vol 272 (3) ◽  
pp. 1440-1443 ◽  
Author(s):  
Elenora García Véscovi ◽  
Youhna M. Ayala ◽  
Enrico Di Cera ◽  
Eduardo A. Groisman
Keyword(s):  
Sensor Protein

scholarly journals P4476Hemodynamic characterization of a transgenic rat strain stably expressing the calcium sensor protein GCaMP2

2017 ◽  
Vol 38 (suppl_1) ◽  
Author(s):  
T. Radovits ◽  
A. Olah ◽  
C. Matyas ◽  
B.T. Nemeth ◽  
M. Ruppert ◽  
...  
Keyword(s):  
Transgenic Rat ◽  
Calcium Sensor ◽  
Sensor Protein ◽  
Rat Strain

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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