Originally published as JHC exPRESS on August 21, 2006.
doi:10.1369/jhc.6A7003.2006
Journal of Histochemistry and Cytochemistry
Volume 54 (12): 1379-1391, 2006
Copyright ©The Histochemical Society, Inc.
Expression of Membrane-bound Carbonic Anhydrases IV, IX, and XIV in the Mouse Heart
Renate J. Scheibe,
Gerolf Gros,
Seppo Parkkila,
Abdul Waheed,
Jeffrey H. Grubb,
Gul N. Shah,
William S. Sly and
Petra Wetzel
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)
Correspondence to: Petra Wetzel, Zentrum Physiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. E-mail: wetzel.petra{at}mh-hannover.de
Expression of membrane-bound carbonic anhydrases (CAs) of CA IV, CA IX, CA XII, and CA XIV has been investigated in the mouse heart. Western blots using microsomal membranes of wild-type hearts demonstrate a 39-, 43-, and 54-kDa band representing CA IV, CA IX, and CA XIV, respectively, but CA XII could not be detected. Expression of CA IX in the CA IV/CA XIV knockout animals was further confirmed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Cardiac cells were immunostained using anti-CA/FITC and anti-
-actinin/TRITC, as well as anti-CA/FITC and anti-SERCA2/TRITC. Subcellular CA localization was investigated by confocal laser scanning microscopy. CA localization in the sarcolemmal (SL) membrane was examined by double immunostaining using anti-CA/FITC and anti-MCT-1/TRITC. 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, whereas 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 excitationcontraction coupling. (J Histochem Cytochem 54:13791391, 2006)
Key Words: carbonic anhydrase cardiomyocytes sarcoplasmic reticulum sarcolemma

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