Glover, Louise and Quinn, Sandra and Ryan, Michelle and Pette, Dirk and Ohlendieck, Kay (2002) Supramolecular calsequestrin complex : Protein–protein interactions in chronic low-frequency stimulated muscle, postnatal development and ageing. European Journal of Biochemistry, 269 (18). pp. 4607-4616. ISSN 0014-2956

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Abstract

As recently demonstrated by overlay assays using calsequestrin-peroxidase conjugates, the major 63 kDa Ca(2+)-binding protein of the sarcoplasmic reticulum forms complexes with itself, and with junctin (26 kDa), triadin (94 kDa) and the ryanodine receptor (560 kDa) [Glover, L., Culligan, K., Cala, S., Mulvey, C. & Ohlendieck, K. (2001) Biochim. Biophys. Acta1515, 120-132]. Here, we show that variations in the relative abundance of these four central elements of excitation-contraction coupling in different fiber types, and during chronic electrostimulation-induced fiber type transitions, are reflected by distinct alterations in the calsequestrin overlay binding patterns. Comparative immunoblotting with antibodies to markers of the junctional sarcoplasmic reticulum, in combination with the calsequestrin overlay binding patterns, confirmed a lower ryanodine receptor expression in slow soleus muscle compared to fast fibers, and revealed a drastic reduction of the RyR1 isoform in chronic low-frequency stimulated tibialis anterior muscle. The fast-to-slow transition process included a distinct reduction in fast calsequestrin and triadin and a concomitant reduction in calsequestrin binding to these sarcoplasmic reticulum elements. The calsequestrin-binding protein junctin was not affected by the muscle transformation process. The increase in calsequestrin and decrease in junctin expression during postnatal development resulted in similar changes in the intensity of binding of the calsequestrin conjugate to these sarcoplasmic reticulum components. Aged skeletal muscle fibers tended towards reduced protein interactions within the calsequestrin complex. This agrees with the physiological concept that the key regulators of Ca(2+) homeostasis exist in a supramolecular membrane assembly and that protein-protein interactions are affected by isoform shifting underlying the finely tuned adaptation of muscle fibers to changed functional demands.

Item Type:	Article
Keywords:	calsequestrin; calcium homeostasis; chronic lowfrequency stimulation; excitation–contraction coupling; ryanodine receptor;
Academic Unit:	Faculty of Science and Engineering > Biology
Item ID:	7515
Identification Number:	https://doi.org/10.1046/j.1432-1033.2002.03160.x
Depositing User:	Prof. Kay Ohlendieck
Date Deposited:	14 Oct 2016 14:51
Journal or Publication Title:	European Journal of Biochemistry
Publisher:	Wiley-Blackwell
Refereed:	Yes
Funders:	Health Research Board (HRB), European Commission
URI:	http://onlinelibrary.wiley.com
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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