Evidence for cardiac sodium-calcium exchanger association with caveolin-3.
The interaction of cardiac Na+-Ca2+ exchange (NCX1) with caveolin proteins was investigated in sarcolemmal vesicles. Western blots of sarcolemmal vesicles revealed the presence of caveolin-1, -2, and -3. NCX1 co-fractionated more closely with caveolin-3 than caveolin-1 on sucrose density gradients. NCX1 has five possible caveolin-binding motifs and NCX1 co-precipitated specifically with caveolin-3. Molecular sieve column chromatography indicated that this co-precipitation was not due to incomplete solubilization of lipid raft microdomains. Cholesterol chelation in vesicles decreased NCX1 transport activity and caveolin-3 co-precipitation. NCX1 may play a role in caveolar transmembrane signaling in addition to its role in excitation-contraction coupling.
Bossuyt
Julie
J
The Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA.
Taylor
Bonnie E
BE
James-Kracke
Marilyn
M
Hale
Calvin C
CC
D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002417:Cattle; D021941:Caveolae / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D051244:Caveolin 3; D022461:Caveolins / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D002784:Cholesterol / Q000378:metabolism; D002850:Chromatography, Gel; D003505:Cyclodextrins / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D012508:Sarcolemma / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000737:chemistry / Q000378:metabolism*
D051244:Caveolin 3; D022461:Caveolins; D003505:Cyclodextrins; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D002784:Cholesterol