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Role of the JP45-Calsequestrin Complex on Calcium Entry in Slow Twitch Skeletal Muscles

Mosca, Barbara and Eckhardt, Jan and Bergamelli, Leda and Treves, Susan and Bongianino, Rossana and De Negri, Marco and Priori, Silvia G. and Protasi, Feliciano and Zorzato, Francesco. (2016) Role of the JP45-Calsequestrin Complex on Calcium Entry in Slow Twitch Skeletal Muscles. Journal of Biological Chemistry, 291 (28). pp. 14555-14565.

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Official URL: http://edoc.unibas.ch/44312/

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Abstract

We exploited a variety of mouse models to assess the roles of JP45-CASQ1 (CASQ, calsequestrin) and JP45-CASQ2 on calcium entry in slow twitch muscles. In flexor digitorum brevis (FDB) fibers isolated from JP45-CASQ1-CASQ2 triple KO mice, calcium transients induced by tetanic stimulation rely on calcium entry via La3+- and nifedipine-sensitive calcium channels. The comparison of excitation-coupled calcium entry (ECCE) between FDB fibers from WT, JP45KO, CASQ1KO, CASQ2KO, JP45-CASQ1 double KO, JP45-CASQ2 double KO, and JP45-CASQ1-CASQ2 triple KO shows that ECCE enhancement requires ablation of both CASQs and JP45. Calcium entry activated by ablation of both JP45-CASQ1 and JP45-CASQ2 complexes supports tetanic force development in slow twitch soleus muscles. In addition, we show that CASQs interact with JP45 at Ca2+ concentrations similar to those present in the lumen of the sarcoplasmic reticulum at rest, whereas Ca2+ concentrations similar to those present in the SR lumen after depolarization-induced calcium release cause the dissociation of JP45 from CASQs. Our results show that the complex JP45-CASQs is a negative regulator of ECCE and that tetanic force development in slow twitch muscles is supported by the dynamic interaction between JP45 and CASQs.
Faculties and Departments:03 Faculty of Medicine > Departement Biomedizin > Department of Biomedicine, University Hospital Basel
03 Faculty of Medicine > Departement Biomedizin > Department of Biomedicine, University Hospital Basel > Perioperative Patient Safety (Girard/Treves)
UniBasel Contributors:Treves, Susan
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Society for Biochemistry and Molecular Biology
ISSN:0021-9258
e-ISSN:1083-351X
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:27 Sep 2017 09:52
Deposited On:18 Oct 2016 11:37

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