RyR1/RyR3 chimeras reveal that multiple domains of RyR1 are involved in skeletal-type E-C coupling

Claudio F. Perez, Andrew Voss, Isaac N Pessah, Paul D. Allen

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Skeletal-type E-C coupling is thought to require a direct interaction between RyR1 and the α1s-DHPR. Most available evidence suggests that the cytoplasmic II-III loop of the dihydropyridine receptor (DHPR) is the primary source of the orthograde signal. However, identification of the region(s) of RyR1 involved in bidirectional signaling with the α1s-DHPR remains elusive. To identify these regions we have designed a series of chimeric RyR cDNAs in which different segments of RyR1 were inserted into the corresponding region of RyR3 and expressed in dyspedic 1B5 myotubes. RyR3 provides a preferable background than RyR2 for defining domains essential for E-C coupling because it possesses less sequence homology to RyR1 than the RyR2 backbone used in previous studies. Our data show that two regions of RyR1 (chimera Ch-10 aa 1681-2641 and Ch-9 aa 2642-3770), were independently able to restore skeletal-type E-C coupling to RyR3. These two regions were further mapped and the critical RyR1 residues were 1924-2446 (Ch-21) and 2644-3223 (Ch-19). These results both support and refine the previous hypothesis that multiple domains of RyR1 combine to functionally interact with the DHPR during E-C coupling.

Original languageEnglish (US)
Pages (from-to)2655-2663
Number of pages9
JournalBiophysical Journal
Volume84
Issue number4
StatePublished - Apr 1 2003

ASJC Scopus subject areas

  • Biophysics

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