Functional importance of polymerization and localization of calsequestrin in C. elegans
Dual roles of calsequestrin (CSQ-1) being the Ca²⁺ donor and Ca²⁺ acceptor make it an excellent Ca²⁺-buffering protein within the sarcoplasmic reticulum (SR). We have isolated and characterized a calsequestrin (csq-1)-null mutant in Caenorhabditis elegans. To our surprise, this mutant csq-1(jh109) s...
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Veröffentlicht in: | Journal of cell science 2007-05, Vol.120 (9), p.1551-1558 |
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Sprache: | eng |
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Zusammenfassung: | Dual roles of calsequestrin (CSQ-1) being the Ca²⁺ donor and Ca²⁺ acceptor make it an excellent Ca²⁺-buffering protein within the sarcoplasmic reticulum (SR). We have isolated and characterized a calsequestrin (csq-1)-null mutant in Caenorhabditis elegans. To our surprise, this mutant csq-1(jh109) showed no gross defects in muscle development or function but, however, is highly sensitive to perturbation of Ca²⁺ homeostasis. By taking advantage of the viable null mutant, we investigated the domains of CSQ-1 that are important for polymerization and cellular localization, and required for its correct buffering functions. In transgenic animals rescued with various CSQ-1 constructs, the in vivo patterns of polymerization and localization of several mutated calsequestrins were observed to correlate with the structure-function relationship. Our results suggest that polymerization of CSQ-1 is essential but not sufficient for correct cellular localization and function of CSQ-1. In addition, direct interaction between CSQ-1 and the ryanodine receptor (RyR) was found for the first time, suggesting that the cellular localization of CSQ-1 in C. elegans is indeed modulated by RyR through a physical interaction. |
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ISSN: | 0021-9533 1477-9137 |
DOI: | 10.1242/jcs.001016 |