High molecular weight proteins in the nematode C. elegans bind [3H]ryanodine and form a large conductance channel

Biophys J. 1992 Nov;63(5):1379-84. doi: 10.1016/S0006-3495(92)81702-2.

Abstract

Single-channel properties of a polypeptide fraction from the nematode Caenorhabditis elegans highly enriched in binding sites were studied in planar bilayers. [3H]Ryanodine binding sites were purified by sucrose gradient centrifugation of C. elegans microsomes solubilized in CHAPS detergent. The highest [3H]ryanodine binding activity sedimented at approximately 18% sucrose (wt/vol), and was composed of a major polypeptide with a M(r) of 360,000 and a minor polypeptide with a M(r) of 170,000. The ryanodine-binding polypeptide(s) formed a Ca(2+)-permeable channel with a permeability ratio P(divalent)/P(monovalent) = 4 and two conductance states of 215 pS and 78 pS in 0.25 M KCl. Ryanodine locked the channel in the 78 pS state and inhibited transitions between the 215 pS and 78 pS states. These data demonstrated the presence of a ryanodine receptor in C. elegans with functional properties comparable to those described in mammalian muscle.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Biophysical Phenomena
  • Biophysics
  • Caenorhabditis elegans / metabolism*
  • Calcium Channels / chemistry
  • Calcium Channels / metabolism*
  • Helminth Proteins / chemistry
  • Helminth Proteins / metabolism*
  • In Vitro Techniques
  • Kinetics
  • Molecular Weight
  • Muscle Proteins / chemistry
  • Muscle Proteins / metabolism
  • Receptors, Cholinergic / chemistry
  • Receptors, Cholinergic / metabolism
  • Ryanodine / metabolism
  • Ryanodine Receptor Calcium Release Channel

Substances

  • Calcium Channels
  • Helminth Proteins
  • Muscle Proteins
  • Receptors, Cholinergic
  • Ryanodine Receptor Calcium Release Channel
  • Ryanodine