cAMP binding proteins in Trypansoma cruzi

EDREIRA, M; MC CORMACK, B; JAGER, AV; DE GAUDENZI, JG; MILD, JG; MUSIKANT, D; PANTANO, S; ALTSCHULER, DL

Cambridge

Congreso; 52nd Annual Spring meeting and Trypanosomiasis and Leishmaniasis symposium; 2014

British Society for Parasitology

Trypanosoma cruzi has a complex life cycle that involves four morphogenetic stages with various second messenger systems capable of regulating its growth and differentiation through signal transduction cascades. Particularly, cAMP-dependent signaling shown to have a crucial role in the proliferation/differentiation and invasion of the host cell. For long, PKA has been considered as the unique cAMP effector. However, in superior eukaryotes a new effector for this second messenger was recently found: EPAC (Exchange Protein directly Activated by cAMP). The absence of sequences for Epac or Epac-like proteins in T. cruzi genome proved that the cAMP-EPAC pathway is not present in the parasite. Although, experimental evidences suggests the existence of PKA-independent pathways in trypanosoma. In order to identify new potential cAMP effectors, we carried out in silico search that identified 27 proteins with putative cAMP binding domains. Phylogenetic analysis made from coding sequence alignments showed that these proteins are segregated into two main branches: one containing protein kinases and the other gathering hypothetical proteins with no assigned function. Putative candidates were expressed in bacteria to experimentally validate these proteins as bona fide cAMP-binding proteins. Consequently, we were able to identify new putative effectors of the PKA-independent pathway in T. cruzi biology.