A PKA survival pathway inhibited by DPT-PKI, a new specific cell permeable PKA inhibitor, is induced by T. annulata in parasitized B-lymphocytes.
T. annulata, an intracellular pathogenic parasite of the Aplicomplexa protozoan family infects bovine B-lymphocytes and macrophages. Parasitized cells that become transformed survive and proliferate independently of exogenous growth factors. In the present study, we used the isogenic non parasitized BL3 and parasitized TBL3 B cell lines, as a model to evaluate the contribution of two-major PI3-K- and PKA-dependent anti-apoptotic pathways in the survival of T. annulata parasitized B lymphocytes. We found that T. annulata increases PKA activity, induces over-expression of the catalytic subunit and down-regulates the pro-survival phosphorylation state of Akt/PKB. Consistent with a role of PKA activation in survival, two pharmacological inhibitors H89 and KT5720 ablate PKA-dependent survival of parasitized cells. To specifically inhibit PKA pro-survival pathways we linked the DPTsh1 peptide shuttle sequence to PKI(5-24) and we generated DPT-PKI, a cell permeable PKI. DPT-PKI specifically inhibited PKA activity in bovine cell extracts and, as expected, also inhibited the PKA-dependent survival of T. annulata parasitized TBL3 cells. Thus, parasite-dependent constitutive activation of PKA in TBL3 cells generates an anti-apoptotic pathway that can protect T. annulata-infected B cells from apoptosis. These results also indicate that DPT-PKI could be a powerful tool to inhibit PKA pathways in other cell types.
Guergnon
Julien
J
Unité de Chimie Organique-Equipe Phosphatase et Laboratoire de signalisation Immunoparasitaire, URA CNRS 2581, 75015 Paris, France.
Dessauge
Frederic
F
Traincard
François
F
Cayla
Xavier
X
Rebollo
Angelita
A
Bost
Pierre Etienne
PE
Langsley
Gordon
G
Garcia
Alphonse
A
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001402:B-Lymphocytes / Q000187:drug effects / Q000469:parasitology*; D002227:Carbazoles / Q000494:pharmacology; D002417:Cattle; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D012694:Serine / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology; D016796:Theileria annulata / Q000502:physiology*; D013801:Theileriasis / Q000503:physiopathology; D015854:Up-Regulation; D051025:bcl-Associated Death Protein / Q000378:metabolism
D002227:Carbazoles; C516424:DPT-PKI protein; D007211:Indoles; D007546:Isoquinolines; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; D011993:Recombinant Fusion Proteins; D013449:Sulfonamides; D051025:bcl-Associated Death Protein; D012694:Serine; C057416:KT 5720; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D017868:Cyclic AMP-Dependent Protein Kinases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide