A cytosolic serine endopeptidase from Trypanosoma cruzi is required for the generation of Ca2+ signaling in mammalian cells.
An early event in the Trypanosoma cruzi cell invasion process, the recruitment of host lysosomes, led us to investigate the involvement of signal transduction. Infective trypomastigotes were found to contain a soluble Ca2+-signaling activity for mammalian cells that is sensitive to protease inhibitors. Inhibitor and substrate utilization profiles were used to purify a candidate peptidase for involvement in this process, from which we isolated a full-length cDNA clone. The sequence revealed a novel enzyme, denominated T. cruzi oligopeptidase B, which is homologous to members of the prolyl oligopeptidase family of serine hydrolases, known to participate in the maturation of biologically active peptides. The T. cruzi oligopeptidase B was expressed as a fully active product in Escherichia coli, and antibodies to the recombinant enzyme inhibited both peptidase activity and Ca2+ signaling induced in normal rat kidney cells by trypomastigote extracts. Our data suggest that the T. cruzi oligopeptidase B participates in processing events in the cytoplasm of the parasites, generating a factor with Ca2+-signaling activity for mammalian cells.
Burleigh
B A
BA
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
Caler
E V
EV
Webster
P
P
Andrews
N W
NW
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D018076:DNA, Complementary; D018628:Gene Dosage; D015870:Gene Expression; D006168:Guinea Pigs; D006867:Hydrolases / Q000737:chemistry; D006868:Hydrolysis / Q000187:drug effects; D008969:Molecular Sequence Data; D000085822:Prolyl Oligopeptidases; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014349:Trypanosoma cruzi / Q000201:enzymology*
D000906:Antibodies; D018076:DNA, Complementary; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D006867:Hydrolases; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases; C090703:oligopeptidase B; D002118:Calcium