Ca(2+)-ATPase distributes differently in cardiac sarcolemma than dihydropyridine receptor alpha 1 subunit and Na+/Ca2+ exchanger.
We have investigated the distribution of the sarcolemmal Ca2+ transporters in hamster and dog ventricular myocytes by immunocytochemical and membrane fractionation techniques. The data suggest that the DHP receptor alpha 1 subunit and the Na+/Ca2+ exchanger are present in surface sarcolemma as well as T-tubule membranes located at the cardiac dyads. Compared with these Ca2+ transporters, the sarcolemmal Ca(2+)-ATPase is much less abundant in the latter fraction. Thus the sarcolemmal Ca(2+)-ATPase seems to be located predominantly in surface sarcolemma.
Iwata
Y
Y
Department of Molecular Physiology, National Cardiovascular Center Research Institute, Osaka, Japan.
Hanada
H
H
Takahashi
M
M
Shigekawa
M
M
D000818:Animals; D020746:Calcium Channels, L-Type; D000252:Calcium-Transporting ATPases / Q000032:analysis*; D002352:Carrier Proteins / Q000032:analysis*; D006224:Cricetinae; D004285:Dogs; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D008861:Microsomes / Q000737:chemistry / Q000201:enzymology; D009124:Muscle Proteins / Q000032:analysis*; D009206:Myocardium / Q000737:chemistry* / Q000201:enzymology; D012508:Sarcolemma / Q000737:chemistry* / Q000201:enzymology; D019831:Sodium-Calcium Exchanger
D020746:Calcium Channels, L-Type; D002352:Carrier Proteins; D009124:Muscle Proteins; D019831:Sodium-Calcium Exchanger; D000252:Calcium-Transporting ATPases