Ref ID : 448
Vigues, B. and Groliere, C.A.; Evidence for a Ca2+ -binding protein associated to non-actin microfilamentous systems in two ciliated protozoans. Exp.Cell Res. 159:366-376, 1985
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Electrophoretic distributions of proteins of isolated cortical cytoskeletons from two ciliated protozoans (Isotricha, Polyplastron) were compared in order to reveal any components common to non-actin microfilamentous structures. A low molecular weight protein (Mr approximately 22 kD) characterized by Ca2+ -induced shifts in mobility on SDS-polyacrylamide gels was identified in both ciliates. Two-dimensional electrophoretic coordinates and peptide maps of Ca2+ -binding proteins from Isotricha and Polyplastron are fairly similar, suggesting conservation of the same molecular species. In addition, an antiserum raised against two proteins (22-23 KD) from the filamentous ecto-endoplasmic boundary of Isotricha, one of which corresponds to the Ca2+ -binding protein, cross-reacts specifically with that of Polyplastron. Using an immunogold staining procedure, the Ca2+ -binding protein of Polyplastron was shown also to be located in a cortical microfilamentous layer. This protein is probably different from calmodulin. We postulate that it is involved in the control of the ordering of non-actin microfilaments within the cortex of ciliates.