title: Ca(2+)- and glycoconjugates-dependent prey capture in the heliozoon Actinophrys sol.
abstract: Exocytosis of extrusomes, secretory granules found in protozoa, is involved in prey capture by the heliozoon Actinophrys sol. Here, we show that extracellular Ca(2+) is necessary for exocytosis and prey capture in A. sol. We found that A. sol could not capture prey cells in a Ca(2+)-free solution. L-type Ca(2+) channel blockers and a calmodulin antagonist also inhibited the capture of prey. These results suggest that Ca(2+) influx via L-type Ca(2+) channels plays a crucial role in exocytosis in A. sol. Concanavalin A (Con A) also inhibited prey capture, and the inhibition was relieved by the addition of its hapten sugar, alpha-mannoside, suggesting that Con A-binding glycoconjugates are implicated in exocytosis of extrusomes and the adhesion of prey cells.
authors.affiliation: Department of Biology, Graduate School of Science, Kobe University, Kobe 657-8501, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Kakuta
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Suzaki
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type; D003208:Concanavalin A / Q000378:metabolism; D056890:Eukaryota / Q000502:physiology*; D005089:Exocytosis; D006001:Glycoconjugates / Q000378:metabolism*; D011235:Predatory Behavior / Q000502:physiology*
chemical_list: D020746:Calcium Channels, L-Type; D006001:Glycoconjugates; D003208:Concanavalin A; D002118:Calcium