Biphasic and dose-dependent accumulation of INSP3 in Trypanosoma cruzi stimulated by a synthetic peptide carrying a chicken alpha D-globin fragment.

A synthetic peptide corresponding to residues 1 to 40 of chicken alpha D-globin stimulated the accumulation of inositol phosphates (InsPs) in Trypanosoma cruzi epimastigotes. This accumulation was shown to be biphasic and dose-dependent. The enhanced inositol trisphosphate (InsP3) accumulation occurred at the third minute with a subsequent increase which is not transient, but sustained over a much longer period. Another peptide carrying residues 35 to 73 was less active. These results evidenced the activation of the phosphoinositide phospholipase C activity in response to peptides that bind specifically to T. cruzi epimastigote cells.