Differential Expression of Calcineurin and SR Ca²⁺ Handling Proteins in Equine Muscle Fibers During Early Postnatal Growth

Karin Eizema ^1*, Dianne E. van der Wal ¹, Maarten M.M. van den Burg ¹, Henriëtte W. de Jonge ¹ and Maria E. Everts ¹

¹ Department of Pathobiology, Division of Anatomy and Physiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands

^* To whom correspondence should be addressed. E-mail: c.g.h.eizema{at}vet.uu.nl.

Submitted on June 23, 2006
Accepted on 30 October 2006

	Abstract

During early postnatal development, the myosin heavy chain (MyHC) expression pattern in equine gluteus medius muscle shows adaptation to movement and load, resulting in a decrease in the number of fast MyHC fibers and an increase in the number of slow MyHC fibers. In the present study, we correlated the expression of MyHC isoforms to the expression of sarcoplasmic(endo)reticulum Ca²⁺-ATPase 1 and 2a (SERCA), phospholamban (PLB), calcineurin A (CnA) and calcineurin B (CnB). Gluteus medius muscle biopsies were taken at 0, 2, 4 and 48 weeks and analyzed using immunofluorescence. Both SERCA isoforms and PLB were expressed in almost all fiber types at birth. From 4 weeks of age onwards, SERCA1 was exclusively expressed in fast MyHC fibers and SERCA2a and PLB in slow MyHC fibers. At all time points CnA and CnB proteins were expressed at a basal level in all fibers, but with a higher expression level in MyHC type 1 fibers. From 4 weeks onwards expression of only CnA was also higher in MyHC type 2a and 2ad fibers. We propose a double function of Calcineurin in calcium homeostasis and maintenance of slow MyHC fiber type identity. Although equine muscle is already functional at birth, the expression patterns of the monitored proteins still show adaptation, depending on the MyHC fiber type.

Key Words: myosin heavy chain, immunofluorescence, signal transduction, differentiation

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. B. Kanatous, T. J. Hawke, S. J. Trumble, L. E. Pearson, R. R. Watson, D. J. Garry, T. M. Williams, and R. W. Davis The ontogeny of aerobic and diving capacity in the skeletal muscles of Weddell seals J. Exp. Biol., August 15, 2008; 211(16): 2559 - 2565. [Abstract] [Full Text] [PDF]

				S.-i. Hino, S. Kondo, H. Sekiya, A. Saito, S. Kanemoto, T. Murakami, K. Chihara, Y. Aoki, M. Nakamori, M. P. Takahashi, et al. Molecular mechanisms responsible for aberrant splicing of SERCA1 in myotonic dystrophy type 1 Hum. Mol. Genet., December 1, 2007; 16(23): 2834 - 2843. [Abstract] [Full Text] [PDF]

Guidelines | Subscriptions | About | exPRESS - Current - Archive | Business Information | Contact

The Journal of Histochemistry & Cytochemistry is owned, published, and licensed by The Histochemical Society © 2006