Status of Ca<sup>2+</sup>/calmodulin protein kinase phosphorylation  of cardiac SR proteins in ischemia-reperfusion

Netticadan, Thomas; Temsah, Rana M.; Osada, Mitsuru; Dhalla, Naranjan S.

doi:10.1152/ajpcell.1999.277.3.c384

Cited by 68 publications

(47 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CaMK phosphorylation of SERCA2a has been reported to increase V max of SR Ca 2ϩ transport (14). Although Odermatt et al (24) failed to demonstrate the CaMK-mediated stimulation of V max of Ca 2ϩ transport, the data from our previous study (10) supported the observation of other investigators (14). SR Ca 2ϩ -release was also shown to be regulated by RyR phosphorylation directly because both CaMK and PKA were reported to promote SR calcium release (25)(26)(27).…”

Section: Diabetes Vol 50 September 2001supporting

confidence: 90%

“…Both the homogenization buffer and the phosphorylation assay medium contained phosphatase inhibitor. SR protein phosphorylations by the endogenous CaMK and exogenously added PKA were determined by the previously described method (10,13). The kinases and phosphatase activities of SR and cytosolic fractions were measured using Upstate Biotechnology assay kits as previously described (10,13).…”

Section: Measurement Of Camentioning

confidence: 99%

“…Insulin treatment did not reverse the diabetes-induced increase in SR CaMK activity. Because a defect in PKA-mediated phosphorylation may also contribute to depressed SR function (10,13), PKA phosphorylation of SR proteins was examined in the control, diabetic, and insulin-treated diabetic hearts. Figure 3 shows the SR protein profile (panel A), the corresponding autoradiogram depicting SR protein phosphorylation (panel B), and the analysis of RyR and PLB phosphorylation by PKA in the control, diabetic, and insulin-treated diabetic groups (panel C).…”

Section: ؉mentioning

confidence: 99%

See 2 more Smart Citations

Depressed Levels of Ca2+-Cycling Proteins May Underlie Sarcoplasmic Reticulum Dysfunction in the Diabetic Heart

et al. 2001

Self Cite

View full text Add to dashboard Cite

In view of the depressed sarcoplasmic reticulum (SR) Ca 2؉-pump and Ca 2؉ -release activities in the diabetic heart and the critical role of phosphorylation in regulating the SR function, we examined the status of Ca -pump ATPase, and phospholamban. On the other hand, the CaMK-and PKA-mediated phosphorylations of these Ca 2؉ -cycling proteins, the endogenous SR CaMK and PKA activities, and the endogenous SR and cytosolic phosphatase activities were increased in the diabetic heart. Treatment of 3-week diabetic animals with insulin partially or fully prevented the diabetesinduced changes in cardiac performance, SR Ca 2؉ -uptake and -release activites, and SR protein content, whereas the diabetes-induced changes in SR CaMK-and PKA-mediated phosphorylations and activities, as well as phosphatase activities, were not significantly affected. These results suggest that the reduced content of the Ca 2؉ -cycling proteins, unlike alterations in PKA and phosphatase activities, appear to be the major defect underlying SR dysfunction in the diabetic heart.

show abstract

Section: Diabetes Vol 50 September 2001supporting

confidence: 90%

Section: Measurement Of Camentioning

confidence: 99%

Section: ؉mentioning

confidence: 99%

See 1 more Smart Citation

Depressed Levels of Ca2+-Cycling Proteins May Underlie Sarcoplasmic Reticulum Dysfunction in the Diabetic Heart

et al. 2001

Self Cite

View full text Add to dashboard Cite

show abstract

“…These studies employ a variety of approaches (in particular immunoprecipitation and heterologous expression of SERCA mutants) to establish the identity of the phosphoprotein critically (24 -26, 30). In other cases the description of SERCA phosphorylation is made on the basis of coincident migration of SERCA and the phosphoprotein in a one-dimensional SDS-PAGE gel (27)(28)(29). This criterion is not sufficiently critical to enable identification of the phosphoprotein, and does not establish whether SERCA is a phosphoprotein.…”

Section: Discussionmentioning

confidence: 99%

Critical Evaluation of Cardiac Ca2+-ATPase Phosphorylation on Serine 38 Using a Phosphorylation Site-specific Antibody

Rodríguez¹,

Jackson²,

Colyer

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

The phosphorylation of the cardiac muscle isoform of the sarcoplasmic reticulum (SR) Ca 2؉ -ATPase (SERCA2a) on serine 38 has been described as a regulatory event capable of very significant enhancement of enzyme activity (Hawkins, C., Xu, A., and Narayanan, N. (1994) J. Biol. Chem. 269, 31198 -31206). Independent confirmation of these observations has not been forthcoming. This study has utilized a polyclonal antibody specific for the phosphorylated serine 38 epitope on the Ca 2؉ -ATPase to evaluate the phosphorylation of SERCA2a in isolated sarcoplasmic reticulum vesicles and isolated rat ventricular myocytes. A quantitative Western blot approach failed to detect serine 38-phosphorylated Ca 2؉ -ATPase in either kinase-treated sarcoplasmic reticulum vesicles or suitably stimulated cardiac myocytes. Calibration standards confirmed that the detection sensitivity of assays was adequate to detect Ser-38 phosphorylation if it occurred on at least 1% of Ca 2؉ -ATPase molecules in SR vesicle experiments or on at least 0.1% of Ca 2؉ -ATPase molecules in cardiac myocytes. The failure to detect a phosphorylated form of the Ca 2؉ -ATPase in either preparation (isolated myocyte, purified sarcoplasmic reticulum vesicles) suggests that Ser-38 phosphorylation of the Ca 2؉ -ATPase is not a significant regulatory feature of cardiac Ca 2؉ homeostasis.Regulation of Ca 2ϩ sequestration by cardiac sarcoplasmic reticulum has been identified as a key control point in cardiac muscle contraction (1, 2). Stimulation of the rate of Ca 2ϩ uptake occurs during exercise, or following ␤-adrenergic stimulation (3) and is associated with an enhanced force of contraction and an increased rate of relaxation. This accounts for much of the positive inotropic and positive lusitropic effects of these interventions. In contrast, Ca 2ϩ sequestration by cardiac SR 1 is abnormally slow in the muscle of individuals with heart failure (4 -6). In animal studies, normalization of the rate of Ca 2ϩ sequestration has been shown to prevent progression of heart failure (7) and thus the molecular mechanism of control of Ca 2ϩ transport into the sarcoplasmic reticulum has become a focus for research into purposeful therapies to combat human heart failure (7,8).Ca 2ϩ transport into cardiac SR is an enzymatic process performed by the (Ca 2ϩ -Mg 2ϩ )-ATPase (9) (or SERCA2a, Ref. 10), a member of the P-type ATPase family (11). The transport process involves the movement of two Ca 2ϩ from the cytoplasm into the lumen of the SR following the hydrolysis of a single molecule of ATP (12), although significantly lower coupling efficiencies have been measured empirically (13). The reaction cycle is relatively slow and thus a large number of SERCA2 molecules are expressed in cardiac muscle (up to 45% of total SR protein content, 14) to achieve the rates of Ca 2ϩ sequestration required by the kinetics of contraction and relaxation.Regulation of Ca 2ϩ transport into the SR occurs on an acute time scale (seconds to minutes) through the transient modification of the proteins inv...

show abstract

“…This long-standing view has been questioned recently, and it has been reported that Ca 2ϩ , but not phosphorylation of PLN, disrupts the interaction between Ca 2ϩ -ATPase and PLN (1). Besides PLN, CaM and CaM kinase are tightly associated with cardiac SR and have been implicated in modulation of Ca 2ϩ uptake and release functions of SR through direct phosphorylation of Ca 2ϩ -ATPase (15,31,32,(43)(44)(45)(46) and RyR CRC (14,38,42).…”

mentioning

confidence: 99%

Mechanistic basis of differences in Ca²⁺-handling properties of sarcoplasmic reticulum in right and left ventricles of normal rat myocardium

Sathish¹,

Xu²,

Karmazyn³

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

transients, evoked by electrical field stimulation, were significantly prolonged in RV myocytes compared with LV myocytes, mainly because of slow decay of intracellular Ca 2ϩ concentration. The slow decay of intracellular Ca 2ϩ concentration in RV and consequent decrease in the speed of RV relaxation may promote temporal synchrony of the end of diastole in RV and LV. The preponderance of functionally silent SR Ca 2ϩ pumps in RV reflects a higher diastolic reserve required to protect and maintain RV function in the face of a sudden rise in afterload or resistance in the pulmonary circulation.calcium-adenosinetriphosphatase; phospholamban; phosphoenzyme; calcium transient; diastolic reserve THE OVERALL EFFECTIVENESS of the heart as a pump is greatly influenced by the interdependence of right ventricular (RV) and left ventricular (LV) function. LV and RV output is primarily determined by the interaction between ventricular preload, the contractile state of the myocardium, and the afterload encountered by the ventricle (16). However, the physiology and hemodynamic functions of RV in the normal state differ considerably from those of LV. For example, afterload, a major determinant of ventricular function, differs nearly sixfold between RV and LV under normal conditions (7).Cardiac adaptation to a variety of physiological stresses is inevitably linked to molecular remodeling of the sarcoplasmic reticulum (SR) Ca 2ϩ -cycling apparatus. The major Ca 2ϩ -cycling proteins in SR include the ryanodine receptor (RyR) Ca 2ϩ release channel (CRC), which is responsible for Ca 2ϩ release into cytosol on myocyte excitation to induce muscle contraction (5); sarco-(endo)plasmic Ca 2ϩ -ATPase (SERCA2a), which actively sequesters Ca 2ϩ back into SR lumen to promote muscle relaxation (18); the Ca 2ϩ -storage protein calsequestrin (27); and phospholamban (PLN), which regulates Ca 2ϩ -ATPase function (23,34,37). In its unphosphorylated state, PLN is thought to interact with Ca 2ϩ -ATPase, exerting an inhibitory effect manifested largely through a decrease in the enzyme's affinity for Ca 2ϩ ; phosphorylation of PLN by cAMP-dependent protein kinase or calmodulin (CaM) kinase is thought to disrupt this interaction, resulting in enhanced affinity of the ATPase for Ca 2ϩ and stimulation of Ca 2ϩ pump activity (23,34,37). This long-standing view has been questioned recently, and it has been reported that Ca 2ϩ , but not phosphorylation of PLN, disrupts the interaction between Ca 2ϩ -ATPase and PLN (1). Besides PLN, CaM and CaM kinase are tightly associated with cardiac SR and have been implicated in modulation of Ca 2ϩ uptake and release functions of SR through direct phosphorylation of Ca 2ϩ -ATPase (15,31,32,(43)(44)(45)(46) and RyR CRC (14,38,42).Increase in afterload of the systemic circulation is known to invoke tissue remodeling and altered Ca 2ϩ homeostasis in LV. However, the impact of physiological load of RV on SR function, to our knowledge, has not been studied. As a first step in exploring the mechanisms of RV adaptation to stress...

show abstract

Status of Ca²⁺/calmodulin protein kinase phosphorylation of cardiac SR proteins in ischemia-reperfusion

Cited by 68 publications

References 27 publications

Depressed Levels of Ca2+-Cycling Proteins May Underlie Sarcoplasmic Reticulum Dysfunction in the Diabetic Heart

Depressed Levels of Ca2+-Cycling Proteins May Underlie Sarcoplasmic Reticulum Dysfunction in the Diabetic Heart

Critical Evaluation of Cardiac Ca2+-ATPase Phosphorylation on Serine 38 Using a Phosphorylation Site-specific Antibody

Mechanistic basis of differences in Ca²⁺-handling properties of sarcoplasmic reticulum in right and left ventricles of normal rat myocardium

Contact Info

Product

Resources

About

Status of Ca2+/calmodulin protein kinase phosphorylation of cardiac SR proteins in ischemia-reperfusion

Cited by 68 publications

References 27 publications

Depressed Levels of Ca2+-Cycling Proteins May Underlie Sarcoplasmic Reticulum Dysfunction in the Diabetic Heart

Depressed Levels of Ca2+-Cycling Proteins May Underlie Sarcoplasmic Reticulum Dysfunction in the Diabetic Heart

Critical Evaluation of Cardiac Ca2+-ATPase Phosphorylation on Serine 38 Using a Phosphorylation Site-specific Antibody

Mechanistic basis of differences in Ca2+-handling properties of sarcoplasmic reticulum in right and left ventricles of normal rat myocardium

Contact Info

Product

Resources

About

Status of Ca²⁺/calmodulin protein kinase phosphorylation of cardiac SR proteins in ischemia-reperfusion

Mechanistic basis of differences in Ca²⁺-handling properties of sarcoplasmic reticulum in right and left ventricles of normal rat myocardium