Cardiac ryanodine receptor activity is altered by oxidizing reagents in either the luminal or cytoplasmic solution

K. R. Eager, A. F. Dulhunty*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    37 Citations (Scopus)

    Abstract

    The location of reactive cysteine residues on the ryanodine receptor (RyR) calcium release channel was assessed from the changes in channel activity when oxidizing or reducing reagents were added to the luminal or cytoplasmic solution. Single sheep cardiac RyRs were incorporated into lipid bilayers with 10-7 M cytoplasmic Ca2+. The thiol specific-lipophilic- 4,4'-dithiodipyridine (4,4'-DTDP, 1 mM), as well as the hydrophilic thimerosal (1 mM), activated and then inhibited RyRs from either the cis (cytoplasmic) or trans (luminal) solutions. Activation was associated with an increase in the (a) mean channel open time and (b) number of exponential components in the open time distribution from one (~2 msec) to three (-1 msec; -7 msec; ~15 msec) in channels activated by trans 4,4'-DTDP or cis or trans thimerosal. A longer component (~75 msec) appeared with cis 4,4'- DTDP. Activation by either oxidant was reversed by the thiol reducing agent, dithiothreitol. The results suggest that three classes of cysteines are available to 4,4'-DTDP or thimerosal, SHa or SHa* activating the channel and SHi closing the channel. SHa is either distributed over luminal and cytoplasmic RyR domains, or is located within the channel pore. SHi is also located within the transmembrane domain. SHa* is located on the cytoplasmic domain of the protein.

    Original languageEnglish
    Pages (from-to)205-214
    Number of pages10
    JournalJournal of Membrane Biology
    Volume167
    Issue number3
    DOIs
    Publication statusPublished - 1999

    Fingerprint

    Dive into the research topics of 'Cardiac ryanodine receptor activity is altered by oxidizing reagents in either the luminal or cytoplasmic solution'. Together they form a unique fingerprint.

    Cite this