Volume 50, Issue 6:

Ultrastructural Distribution of the S100A1 Ca2+-Binding Protein in the Human Heart

B. MACO1, A. MANDINOVA2, M. B. DÜRRENBERGER2, B. W. SCHÄFER3, B. UHRÍK1,
C. W. HEIZMANN3


1Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia, 2Maurice E. Müller-Institute, Biocentrum, University of Basel, Basel, Switzerland, 3Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zurich, Zurich, Switzerland

Received October 26, 2000
Accepted March 26, 2001


Summary
Impaired calcium homeostasis and altered expression of Ca2+-binding proteins are associated with cardiomyopathies, myocardial hypertrophy, infarction or ischemia. S100A1 protein with its modulatory effect on different target proteins has been proposed as one of potential candidates which could participate in these pathological processes. The exact localization of S100A1 in human heart cells on the ultrastructural level accompanied with biochemical determination of its target proteins may help clarify the role of S100A1 in heart muscle. In the present study the distribution of the S100A1 protein using postembedding (Lowicryl K4M) immunocytochemical method in human heart muscle has been determined quantitatively, relating number of antigen sites to the unit area of a respective structural component. S100A1 antigen sites have been detected in elements of sarcoplasmic reticulum (SR), in myofibrils at all levels of sarcomere and in mitochondria, the density of immunolabeling at Z-lines being about 3 times and at SR more than 5 times higher than immunolabeling of remaining structural components. The presence of the S100A1 in SR and myofibrils may be related to the known target proteins for S100A1 at these sites.


Key words
Human heart muscle · Ca2+-binding proteins · S100A1 · Immunocytochemistry

Reprint requests
B. Uhrík, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovak Republic. Fax: +421-2-5477-3666, E-mail: umfguhrk@savba.savba.sk

 

PHYSIOLOGICAL RESEARCH
© 2001 by the Institute of Physiology,
Czech Academy of Sciences

ISSN 0862 - 8408

Issue 6