title: Intracellular signaling transduction in the differentiation of Trypanosoma cruzi: role of cAMP.
abstract: We have studied the cell differentiation of Trypanosoma cruzi in an vitro system that allows the transformation of epimastigotes into metacyclic trypomastigotes. Intracellular cAMP levels of epimastigotes increased 3 fold prior to their differentiation into metacyclics where cAMP remained elevated 3.7 fold with respect to epimastigotes. We also observed a 3 fold increase in the specific activity of cAMP-binding of metacyclics crude homogenates. This activity resided in a cAMP-binding receptor protein (CARPT) which was different from the typical cAMP-binding subunits (RI and RII) of cAMP-dependent protein kinases, as shown by the use of polyclonal antibodies prepared against these two types of proteins. Anti-RI antibodies did not react with CARPT, and anti-RII antibodies gave a cross reaction with CARPT which was at least 1,000 fold less sensitive than the one shown by the homologous antigen. On Western blots CARPT displayed a major band with Mr = 87,000 instead of Mr = 56,000 for RII. These studies implicate that cAMP may act as a mediator of the cell differentiation of T. cruzi by a mechanism involving a novel type of cAMP-binding receptor.
authors.affiliation: Centro de Investigaciones Biomédicas, Universidad de Carabobo, Maracay, Venezuela.
authors.forename: R
authors.initials: R
authors.lastname: Rangel-Aldao
authors.forename: F
authors.initials: F
authors.lastname: Triana
authors.forename: G
authors.initials: G
authors.lastname: Comach
authors.forename: T
authors.initials: T
authors.lastname: Abate
authors.forename: V
authors.initials: V
authors.lastname: Fernández
authors.forename: D
authors.initials: D
authors.lastname: McMahon-Pratt
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology*; D002373:Cyclic AMP Receptor Protein; D011953:Receptors, Cyclic AMP / Q000502:physiology; D015398:Signal Transduction; D014349:Trypanosoma cruzi / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D011953:Receptors, Cyclic AMP; D000242:Cyclic AMP