Extruded trichocysts are composed of a family of proteins with molecular weights between 15,000 and 20,000. We have used heat treatment and affinity chromatography on fluphenazine-Sepharose to purify calmodulinlike proteins from whole cells and from extruded trichocysts. The purified protein from trichocysts is indistinguishable from that of whole cells; it is heat-stable, activates brain phosphodiesterase in a Ca++-dependent fashion, changes mobility on SDS polyacrylamide gels in the presence of Ca++, contains 1 mol of trimethyllysine/17 kdaltons, and has the amino acid composition characteristic of calmodulins. Calmodulin is a major component of purified, extruded trichocysts, of which it represents between 1 and 10% by mass. The other proteins of the trichocyst also resemble calmodulin in several properties. Possible roles for calmodulin in the Ca++-activated extrusion of trichocysts is discussed.
Report| February 22 1981
Calmodulin is a major component of extruded trichocysts from Paramecium tetraurelia.
J J Rauh
D L Nelson
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1981) 91 (3): 860–865.
J J Rauh, D L Nelson; Calmodulin is a major component of extruded trichocysts from Paramecium tetraurelia.. J Cell Biol 1 December 1981; 91 (3): 860–865. doi: https://doi.org/10.1083/jcb.91.3.860
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