Expression of sarcoplasmic-endoplasmic reticulum Ca-ATPase isoforms in masticatory muscles
Version of Record online: 14 NOV 2013
© 2013 Eur J Oral Sci
European Journal of Oral Sciences
Volume 122, Issue 1, pages 36–41, February 2014
How to Cite
Expression of sarcoplasmic-endoplasmic reticulum Ca-ATPase isoforms in masticatory muscles. Eur J Oral Sci 2014; 122: 36–41. © 2013 Eur J Oral Sci, , , , .
- Issue online: 9 JAN 2014
- Version of Record online: 14 NOV 2013
- Manuscript Accepted: 21 SEP 2013
- University of Buenos Aires, Argentina. Grant Number: UBACyT 20020110100082
- masticatory muscles;
- sarcoplasmic reticulum;
- sarcoplasmic-endoplasmic reticulum Ca2+-dependent adenosine triphosphatase
The aim of this study was to characterize the sarcoplasmic-endoplasmic reticulum Ca-ATPase (SERCA) isoforms in rabbit masticatory muscles compared with those in fast-twitch muscle. It was hypothesized that combined expression of the SERCA isoforms in fast- and slow-twitch muscles accounts for lower Ca-ATPase activity. SERCA was isolated by differential centrifugation, the isoforms were determined by ELISA, and the activity of each isoform was measured using a colorimetric method. Activity was tested for significance by anova, and the distribution of isoforms was assessed using the chi-square test (P < 0.05) and correlated to SERCA activity using Spearman's rank correlation. SERCA1 was predominant (90.5%) in fast-twitch muscle, whereas a mixture of SERCA isoforms was found in masticatory muscles: 62–78% was SERCA2, 20–37% was SERCA1, and the SERCA3 content was negligible. Depressor muscles showed a significantly higher content (77.8%) of SERCA2, and elevator muscles showed a higher content (35.4%) of SERCA1. Elevator muscles showed higher expression of SERCA2a (58%), and depressor muscles showed higher expression of SERCA2b (20%). The SERCA1 content was mainly SERCA1a and significantly higher for elevator muscles (33%), whereas depressor muscles showed a higher content of SERCA1b (4%). The SERCA1 content of fast-twitch muscle was mainly SERCA1a (88.5%). It is concluded that the mixture of different SERCA isoforms, along with a substantial content of SERCA2b, in masticatory muscles would support lower Ca-ATPase activity and calcium transport.