Effects of lanthanum on the heart sarcolemmal ATPase and calcium binding activities

1979 ◽  
Vol 57 (5) ◽  
pp. 496-503 ◽  
Author(s):  
Satoshi Takeo ◽  
Peter Duke ◽  
Gina M. L. Taam ◽  
Pawan K. Singal ◽  
Naranjan S. Dhalla
Keyword(s):  
Atpase Activity ◽  
Calcium Binding ◽  
Calcium Concentration ◽  
Treatment Method ◽  
Binding Activity ◽  
Outer Cell ◽  
Control Value ◽  
Rat Hearts ◽  
Dense Deposits ◽  
Perfused Hearts

Effects of lanthanum on Ca2+-ATPase, Mg2+-ATPase, Na+–K+-ATPase, and calcium binding activities were studied in rat heart sarcolemma. Ten to 100 μM lanthanum depressed significantly the Ca2+-ATPase activity and 50–200 μM lanthanum inhibited the calcium binding activity. Lineweaver–Burk plots of the Ca2+-ATPase activity showed that the inhibition by lanthanum was competitive with calcium concentration. Neither Mg2+-ATPase nor Na+–K+-ATPase activities were affected by lanthanum when the assay medium contained 1 mM EDTA; however, in the absence of EDTA, these enzyme activities were significantly decreased by 10–100 μM lanthanum. Rat hearts perfused with HEPES buffer containing 0.5 mM lanthanum showed electron-dense deposits restricted to the outer cell surface and the sarcolemma obtained from these hearts also had the deposits, indicating that the membrane fraction isolated by the hypotonic shock – LiBr treatment method is of sarcolemmal origin. The Ca2+-ATPase activity of the sarcolemma isolated from lanthanum-perfused hearts, unlike the Mg2+-ATPase, Na+–K+-ATPase, and calcium binding activities, was significantly less than the control value. From these observations it is suggested that lanthanum may influence calcium movement across the sarcolemma by affecting sarcolemmal ATPase and calcium binding activities.

Changes in subcellular membranes in rat heart perfused with diethyl ether

1979 ◽  
Vol 57 (12) ◽  
pp. 1412-1420
Author(s):  
Gina M. L. Taam ◽  
Satoshi Takeo ◽  
Vincenzo Panagia ◽  
Attila Ziegelhoffer ◽  
Naranjan S. Dhalla
Keyword(s):  
Calcium Binding ◽  
Electron Microscopic Examination ◽  
Membrane System ◽  
Contractile Force ◽  
Perfused Heart ◽  
Electron Microscopic ◽  
Irreversible Damage ◽  
Control Value ◽  
Subcellular Membrane ◽  
Rat Hearts

Alterations in contractile force as well as heart sarcolemmal, microsomal, and mitochondrial activities were investigated by perfusing rat hearts with different concentrations (0.5–1.5% (v/v)) of ether for 2 min. Contractile force of the perfused heart was depressed by 0.5–1.0% ether and completely abolished by 1.25–1.5% ether. The contractile force recovered fully upon reperfusion when the hearts were preperfused with 0.5–0.75% ether but the recovery was partial in hearts preperfused with 1.0–1.25% ether. The hearts preperfused with 1.5% ether did not recover their ability to generate contractile force upon reperfusion. The Na+–K+-ATPase activity of sarcolemma obtained from hearts perfused with 0.75–1.0% ether was higher than the control value. The sarcolemmal Na+–K+-ATPase, Mg2+-ATPase, Ca2+-ATPase, calcium binding, and adenylate cyclase activities were decreased in hearts perfused with 1.5% ether and these activities were further decreased upon reperfusion. The microsomal calcium binding and uptake activities were depressed in hearts perfused with 1.0–1.5% ether and these changes were irreversible. The mitochondrial calcium binding and uptake activities as well as oxidative phosphorylation activity were also depressed in hearts perfused with 1.0–1.5% ether; however, irreversible damage was seen in hearts perfused with 1.5% ether. Electron microscopic examination showed occasional vacuolization of mitochondria in hearts perfused with 1% ether and swelling of sarcoplasmic reticulum and mitochondria as well as damage to myofilaments were seen in hearts perfused with 1.5% ether. These results suggest the involvement of alterations in subcellular membrane system in the cardiotoxic actions of ether.

Contractile proteins and sarcoplasmic reticulum in physiologic cardiac hypertrophy

1981 ◽  
Vol 241 (2) ◽  
pp. H263-H267 ◽  
Author(s):  
A. Malhotra ◽  
S. Penpargkul ◽  
T. Schaible ◽  
J. Scheuer
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Calcium Binding ◽  
Wistar Rats ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Contractile Proteins ◽  
Heart Weight ◽  
Female Wistar Rats ◽  
Female Control

To study effects of physiologic hypertrophy on contractile protein ATPases and sarcoplasmic reticulum, hypertrophy was caused in female Wistar rats by a chronic swimming program. Nonhypertrophied hearts of female control sedentary rats and rats made to run on a treadmill program were also examined. The swimming program, but not the running program, resulted in a significant increase in heart weight. Actomyosin ATPase activity was also increased by 15% in the hearts of swimmers but not runners. Similar increases were observed for Ca2+-activated myosin ATPase activity and actin-activated ATPase of myosin. Sarcoplasmic reticulum from the hearts of swimmers showed increased calcium binding and calcium uptake as a function of time and of calcium concentration. Sarcoplasmic reticulum ATPase activities were not altered by hypertrophy. These findings in physiologic hypertrophy contrast with those of pathologic hypertrophy in which ATPase activity of contractile proteins and calcium binding and uptake of sarcoplasmic reticulum have generally been found to be depressed.

Effect of calcium concentration on isolated hamster brain Na-K-, Mg-dependent ATPase

1982 ◽  
Vol 60 (8) ◽  
pp. 1119-1124 ◽  
Author(s):  
F. Rohani ◽  
J. D. Welty ◽  
D. F. Hastings
Keyword(s):  
Atpase Activity ◽  
Binding Site ◽  
Calcium Binding ◽  
Calcium Concentration ◽  
Specific Activity ◽  
Hill Coefficient ◽  
Affinity Binding ◽  
Dependent Atpase ◽  
Positive Cooperativity

In these experiments the effect of different concentrations of calcium on the specific activity of isolated Na-K-ATPase was studied. The result of these investigations showed that calcium at 10−6 and 10−7 M stimulated the Na-K-ATPase activity. These studies also show that at higher calcium concentrations (10−5–10−3 M), the activity of the enzyme is inhibited. The results from calcium binding to isolated membranes, rich in Na-K-ATPasc, strongly suggest the existence of a low-affinity binding site which exhibits a large positive cooperativity, Kd = 2.8 × 10−5 ± 0.4 × 10−5 M and Hill coefficient of 2.9 ± 0.2. The calcium concentration (1.9 × 10−5 M sufficient to produce significant (24%) inhibition of the Na-K-ATPase is approximately equal to the Kd observed for calcium binding.

scholarly journals Nonstructural 5A Protein of Hepatitis C Virus Regulates Soluble Resistance-Related Calcium-Binding Protein Activity for Viral Propagation

2015 ◽  
Vol 90 (6) ◽  
pp. 2794-2805 ◽  
Author(s):  
Giao V. Q. Tran ◽  
Trang T. D. Luong ◽  
Eun-Mee Park ◽  
Jong-Wook Kim ◽  
Jae-Woong Choi ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Interaction ◽  
Calcium Binding ◽  
Crucial Role ◽  
Binding Protein ◽  
Binding Activity ◽  
Calcium Binding Protein ◽  
Virus Propagation ◽  
Ns5a Protein

ABSTRACTHepatitis C virus (HCV) is a major cause of chronic liver disease and is highly dependent on cellular proteins for virus propagation. To identify the cellular factors involved in HCV propagation, we recently performed protein microarray assays using the HCV nonstructural 5A (NS5A) protein as a probe. Of 90 cellular protein candidates, we selected the soluble resistance-related calcium-binding protein (sorcin) for further characterization. Sorcin is a calcium-binding protein and is highly expressed in certain cancer cells. We verified that NS5A interacted with sorcin through domain I of NS5A, and phosphorylation of the threonine residue 155 of sorcin played a crucial role in protein interaction. Small interfering RNA (siRNA)-mediated knockdown of sorcin impaired HCV propagation. Silencing of sorcin expression resulted in a decrease of HCV assembly without affecting HCV RNA and protein levels. We further demonstrated that polo-like kinase 1 (PLK1)-mediated phosphorylation of sorcin was increased by NS5A. We showed that both phosphorylation and calcium-binding activity of sorcin were required for HCV propagation. These data indicate that HCV modulates sorcin activity via NS5A protein for its own propagation.IMPORTANCESorcin is a calcium-binding protein and regulates intracellular calcium homeostasis. HCV NS5A interacts with sorcin, and phosphorylation of sorcin is required for protein interaction. Gene silencing of sorcin impaired HCV propagation at the assembly step of the HCV life cycle. Sorcin is phosphorylated by PLK1 via protein interaction. We showed that sorcin interacted with both NS5A and PLK1, and PLK1-mediated phosphorylation of sorcin was increased by NS5A. Moreover, calcium-binding activity of sorcin played a crucial role in HCV propagation. These data provide evidence that HCV regulates host calcium metabolism for virus propagation, and thus manipulation of sorcin activity may represent a novel therapeutic target for HCV.

scholarly journals The Heparin-Binding Activity of Secreted Modular Calcium-Binding Protein 1 (SMOC-1) Modulates Its Cell Adhesion Properties

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e56839 ◽  
Author(s):  
Marina Klemenčič ◽  
Marko Novinec ◽  
Silke Maier ◽  
Ursula Hartmann ◽  
Brigita Lenarčič
Keyword(s):  
Cell Adhesion ◽  
Calcium Binding ◽  
Binding Protein ◽  
Binding Activity ◽  
Calcium Binding Protein ◽  
Heparin Binding ◽  
Adhesion Properties

Abstract 5402: Two Photon Microscopy Measurements Of Sub-epicardial Sarcomere Length In Perfused Rat Hearts

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Patrizia Camelliti ◽  
Gil Bub ◽  
Daniel J Stuckey ◽  
Christian Bollensdorff ◽  
Damian J Tyler ◽  
...  
Keyword(s):  
Sarcomere Length ◽  
Left Ventricular ◽  
Model Systems ◽  
Future Research ◽  
Fundamental Parameter ◽  
Rat Hearts ◽  
Perfused Hearts ◽  
Over Time

Sarcomere length (SL) is a fundamental parameter underlying the Frank Starling relation in the heart, as it offers an absolute representation of myocardial stretch. Previous studies addressed the Frank Starling relation by measuring SL in isolated myocytes or muscle strips. Here, we report first data obtained using a novel technique to measure sub-epicardial SL in perfused hearts. Rat hearts were Langendorff perfused (normal Tyrode solution) at a constant pressure of 90mmHg, labeled with the fluorescent membrane marker di-4-ANEPPS, and then arrested with high-K + Tyrode for either 2-photon microscopy (n=4) or MRI (n=4). Image analysis software was developed to extract SL at the cell level from >1,400 2-photon images (Fig 1 ) and correct for cell angle. SL increased by 10±2 % between 30 and 80 min of perfusion (1.98±0.04 to 2.17±0.03 μm; p<0.05; Fig 1 ). Measurements of left ventricular myocardial volume (LVMV) were made in vivo and in perfused hearts using 3D MRI. LVMV increased by 24±7% from in vivo to 30 min of perfusion, and by 11±3 % between 30 and 90 min (539±35; 664±44; 737±49 mm 3 , respectively; p<0.05; Fig 1 ). We show that SL can be measured in isolated perfused hearts. The method allowed monitoring of changes in SL over time, and showed that SL and LVMV increase to a similar extent during 30–80 min perfusion with crystalloid solution, probably due to tissue oedema. This result, together with the increase in LVMV during the first 30 min, highlights the pronounced differences between in vivo , in situ , and in vitro model systems for studies of cardiac physiology and mechanics. Future research will compare changes in SL in healthy hearts and disease models involving contractile dysfunction. Figure 1: Left: 2-photon microscopy image of di-4-ANEPPS labeled myocardium. Right: SL and LVMV changes over time.

Comparative force-velocity relation and analyses of myosin of dog atria and ventricles

1982 ◽  
Vol 243 (3) ◽  
pp. H391-H397 ◽  
Author(s):  
J. Wikman-Coffelt ◽  
H. Refsum ◽  
G. Hollosi ◽  
L. Rouleau ◽  
L. Chuck ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Calcium Concentration ◽  
Maximum Velocity ◽  
Calcium Sensitivity ◽  
Myofibrillar Proteins ◽  
Maximal Velocity ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Normal Calcium ◽  
Actin Concentration

The isolated muscle and purified myofibrillar proteins of canine atria and ventricles were compared relative to force-velocity relations and rate of adenosine 5'-triphosphatase (ATPase) activity as a function of calcium concentrations. The maximal stress development of isolated trabeculae of canine atria was similar to that of canine right ventricular papillary muscles when analyzed at saturating calcium concentrations (7.5 mM); however, stress was less in the atria when studied at normal calcium concentrations (2.5 mM). The maximal velocity of shortening of atrial trabeculae was about 2.3 times higher than that of ventricular muscle. Regulated actomyosin characterized from the myofibrillar proteins of the two tissues gave directionally similar calcium sensitivity. The maximum velocity of shortening for actin-activated atrial myosin of the dog was approximately 1.8 times higher when the latter was analyzed as a function of actin concentration. Both maximal tension of isolated muscle and regulated actomyosin ATPase activity were dependent on calcium concentration.

Isolated working rat heart perfusion with perfluorochemical emulsion Fluosol-43

1982 ◽  
Vol 242 (4) ◽  
pp. H485-H489 ◽  
Author(s):  
L. D. Segel ◽  
S. V. Rendig
Keyword(s):  
Lactate Concentration ◽  
Systolic Pressure ◽  
Colloid Osmotic Pressure ◽  
Left Ventricular ◽  
Mechanical Function ◽  
External Work ◽  
Bicarbonate Buffer ◽  
Rat Hearts ◽  
Perfluorochemical Emulsion ◽  
Perfused Hearts

Isolated working rat hearts were perfused with the perfluorochemical emulsion Fluosol-43 to determine whether it would support prolonged, stable cardiac function. The perfluorochemical emulsion provides a controlled perfusate composition, relatively high oxygen capacity, and a colloid osmotic pressure that is similar to that of plasma. Electrically paced (325 beats/min) hearts were perfused for 6 h at 35 degrees C in a recirculating system. Hemodynamic and mechanical function of seven Krebs-Henseleit-perfused hearts declined significantly more than that of seven Fluosol-43-perfused hearts over the 6-h period. The percent of initial function remaining at 6 h for Krebs-Henseleit-perfused vs. Fluosol-43-perfused hearts was 70.3 +/- 5.0 vs. 95.4 +/- 1.1% (P less than 0.001) for left ventricular peak systolic pressure; 55.6 +/- 7.7 vs. 97.5 +/- 2.4% (P less than 0.001) for dP/dtmax; 27.1 +/- 7.2 vs. 60.6 +/- 5.2% (P less than 0.005) for cardiac output; 11.0 +/- 6.3 vs. 67.2 +/- 3.4% (P less than 0.001) for external work efficiency; and 17.4 +/- 8.4 vs. 67.7 +/- 4.5% (P less than 0.001) for stroke rhythmic than Fluosol-43-perfused hearts during the last 3 h of perfusion. Perfusate lactate concentration was 4.5-fold higher in the Krebs-Henseleit perfusate than in the Fluosol-43 perfusate at 6 h, reflecting greater anaerobic metabolism in the Krebs-Henseleit-perfused hearts. Thus isolated rat hearts perfused with Fluosol-43 have greater maintenance of hemodynamic and mechanical function over a longer time period than hearts perfused with Krebs-Henseleit bicarbonate buffer.

scholarly journals Increased Ca++, Mg++, and Na+ + K+ ATPase activities in erythrocytes of sickle cell anemia

Blood ◽  
1982 ◽  
Vol 60 (6) ◽  
pp. 1332-1336 ◽  
Author(s):  
MG Luthra ◽  
DA Sears
Keyword(s):  
Enzyme Activity ◽  
Blood Cell ◽  
Atpase Activity ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Red Blood Cell ◽  
Calcium Binding ◽  
Red Cells ◽  
Low Density ◽  
Red Cell

Abstract To determine whether diminished activity of the Ca++ extrusion pump could account for the high levels of red blood cell (RBC) Ca++ in sickle cell anemia (SS), we measured calmodulin-sensitive Ca++ ATPase activity in normal and SS RBC. Hemolysates prepared with saponin were compared, since such preparations expressed maximum ATPase activities, exceeding isolated membranes or reconstituted systems of membranes plus cytosol, SS RBC hemolysates had greater Ca++ ATPase activity than normal hemolysates; they exhibited higher Mg++ and Na+ + K+ ATPase activities as well. Assays on density (age) fractions of SS and normal red cells demonstrated that all ATPase activities were highest in low density (young) cells, and activities in SS red cells exceeded those in normals in all fractions studied. Thus, when studied under conditions that maximize enzyme activity, Ca++ ATPase activity, like Mg++ and Na+ + K+ ATPase, is actually increased in SS RBC, probably due to the young red cell population present. The elevated Ca++ levels in these cells are more likely due to an increased Ca++ leak or abnormal calcium binding than to defective extrusion by the ATPase pump.

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