Phospholemman-phosphorylation mediates the β-adrenergic effects on Na/K pump function in cardiac myocytes

被引:153
作者
Despa, S
Bossuyt, J
Han, F
Ginsburg, KS
Jia, LG
Kutchai, H
Tucker, AL
Bers, DM
机构
[1] Loyola Univ, Dept Physiol, Stritch Sch Med, Maywood, IL 60153 USA
[2] Univ Virginia, Charlottesville, VA USA
关键词
Na pump; phospholemman; signal transduction; ion channels;
D O I
10.1161/01.RES.0000176532.97731.e5
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Cardiac sympathetic stimulation activates beta-adrenergic (beta-AR) receptors and protein kinase A (PKA) phosphorylation of proteins involved in myocyte Ca regulation. The Na/K-ATPase (NKA) is essential in regulating intracellular [Na] ([Na](i)), which in turn affects [Ca](i) via Na/Ca exchange. However, how PKA modifies NKA function is unknown. Phospholemman (PLM), a member of the FXYD family of proteins that interact with NKA in various tissues, is a major PKA substrate in heart. Here we tested the hypothesis that PLM phosphorylation is responsible for the PKA effects on cardiac NKA function using wild-type (WT) and PLM knockout (PLM-KO) mice. We measured NKA-mediated [Na](i) decline and current (I-Pump) to assess beta-AR effects on NKA function in isolated myocytes. In WT myocytes, 1 mu mol/L isoproterenol (ISO) increased PLM phosphorylation and stimulated NKA activity mainly by increasing its affinity for internal Na (K-m decreased from 18.8 +/- 1.4 to 13.6 +/- 1.5 mmol/L), with no significant effect on the maximum pump rate. This led to a significant decrease in resting [Na](i) (from 12.5 +/- 1.8 to 10.5 +/- 1.4 mmol/L). In PLM-KO mice under control conditions K-m (14.2 +/- 1.5 mmol/L) was lower than in WT, but comparable to that for WT in the presence of ISO. Furthermore, ISO had no significant effect on NKA function in PLM-KO mice. ATPase activity in sarcolemmal vesicles also showed a lower K-m(Na) in PLM-KO versus WT (12.9 +/- 0.9 versus 16.2 +/- 1.5). Thus, PLM inhibits NKA activity by decreasing its [Na](i) affinity, and this inhibitory effect is relieved by PKA activation. We conclude that PLM modulates the NKA function in a manner similar to the way phospholamban affects the related SR Ca-ATPase (inhibition of transport substrate affinity, that is relieved by phosphorylation).
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页码:252 / 259
页数:8
相关论文
共 37 条
[1]   The γ subunit modulates Na+ and K+ affinity of the renal Na,K-ATPase [J].
Arystarkhova, E ;
Wetzel, RK ;
Asinovski, NK ;
Sweadner, KJ .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1999, 274 (47) :33183-33185
[2]   Physical interactions between phospholamban and sarco(endo)plasmic reticulum Ca2+-ATPases are dissociated by elevated Ca2+, but not by phospholamban phosphorylation, vanadate, or thapsigargin, and are enhanced by ATP [J].
Asahi, M ;
McKenna, E ;
Kurzydlowski, K ;
Tada, M ;
MacLennan, DH .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (20) :15034-15038
[3]   Intracellular Na+ regulation in cardiac myocytes [J].
Bers, DM ;
Barry, WH ;
Despa, S .
CARDIOVASCULAR RESEARCH, 2003, 57 (04) :897-912
[4]   SODIUM-CALCIUM EXCHANGE AND SIDEDNESS OF ISOLATED CARDIAC SARCOLEMMAL VESICLES [J].
BERS, DM ;
PHILIPSON, KD ;
NISHIMOTO, AY .
BIOCHIMICA ET BIOPHYSICA ACTA, 1980, 601 (02) :358-371
[5]  
BOSSUYT J, 2005, UNPUB CIRC RES
[6]   Functional regulation of reconstituted Na,K-ATPase by protein kinase A phosphorylation [J].
Cornelius, F ;
Logvinenko, N .
FEBS LETTERS, 1996, 380 (03) :277-280
[7]   Phospholemman (FXYD1) associates with Na,K-ATPase and regulates its transport properties [J].
Crambert, G ;
Füzesi, M ;
Garty, H ;
Karlish, S ;
Geering, K .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2002, 99 (17) :11476-11481
[8]   Frequency-dependent acceleration of relaxation in the heart depends on CaMKII, but not phospholamban [J].
DeSantiago, J ;
Maier, LS ;
Bers, DM .
JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY, 2002, 34 (08) :975-984
[9]   ISOPROTERENOL DIRECTLY STIMULATES THE NA+-K+ PUMP IN ISOLATED CARDIAC MYOCYTES [J].
DESILETS, M ;
BAUMGARTEN, CM .
AMERICAN JOURNAL OF PHYSIOLOGY, 1986, 251 (01) :H218-H225
[10]   Na/K pump current and [Na]i in rabbit ventricular myocytes:: Local [Na]i depletion and Na buffering [J].
Despa, S ;
Bers, DM .
BIOPHYSICAL JOURNAL, 2003, 84 (06) :4157-4166