Copyright © Histochemical Society, Inc. A more recent version of this article appeared on December 1, 2006.
Expression of Membrane-bound Carbonic Anhydrases IV, IX, and XIV in the Mouse Heart
1 Zentrum Physiologie, Medizinische Hochschule Hannover, Hannover, Germany (RJS,GG, PW); Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri (AW,JHG,GNS,WSS); and Institute of Medical Technology, University of Tampere and Tampere University Hospital, Tampere, Finland (SP)
* To whom correspondence should be addressed. E-mail: wetzel.petra{at}mh-hannover.de.
-actinin/TRITC as well as anti-CA/FITC and anti-SERCA2/TRITC. The subcellular CA localization was investigated by confocal laser scanning microscopy. The CA localization in the sarcolemmal (SL) membrane was examined by double immunostaining using anti-CA/FITC and anti-MCT-1/TRITC. The CAs showed a distinct distribution pattern in the sarcoplasmic reticulum (SR) membrane. CA XIV is predominantly localized in the longitudinal SR, whereas CA IX is mainly expressed in the terminal SR/t-tubular region. CA IV is present in both SR regions, while CA XII is not found in the SR. In the SL membrane, only CA IV and CA XIV are present. We conclude that CA IV and CA XIV are associated with the SR as well as with the SL membrane, CA IX is located in the terminal SR/t-tubular region, and CA XII is not present in the mouse heart. Therefore, the unique subcellular localization of CA IX and CA XIV in cardiac myocytes suggests different functions of both enzymes in excitation-contraction coupling.
Key Words: carbonic anhydrase, cardiomyocytes, sarcoplasmic reticulum, sarcolemma
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