Protein kinase A catalytic subunit interacts and phosphorylates members of trans-sialidase super-family in Trypanosoma cruzi

Microbes Infect. 2010 Sep;12(10):716-26. doi: 10.1016/j.micinf.2010.04.014. Epub 2010 May 11.


Protein kinase A (PKA) has been suggested as a regulator of stage differentiation in Trypanosoma cruzi. Using a yeast two-hybrid system we have begun to characterize the downstream substrates of T. cruzi PKA. We identified several members of the trans-sialidase super family by this approach. Immunoprecitation demonstrated that a TcPKAc monoclonal antibody was able to pull-down proteins recognized by trans-sialidase antibodies as well as a SA85-1.1 antibody and vice versa. An in vitro phosphorylation assay demonstrated that PKA phosphorylated the recombinant protein of an active trans-sialidase. In addition, a phospho-(Ser/Thr) PKA substrate antibody detected bands on immunoblot analysis of trans-sialidase antibody precipitated proteins from parasite lysate and the media of L(6)E(9) myoblasts infected with trypomastigotes as well as from a SA85-1.1 antibody precipitated proteins from parasite lysate. Immunofluorescence analysis suggested that some TcPKAc localizes to the plasma membrane surface of trypomastigotes. The identified trans-sialidases have PKA consensus phosphorylation sites located near the endoplasmic reticulum retention motif in the N-terminal. These data support that PKA phosphorylates trans-sialidase super family members in vivo.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Catalytic Domain
  • Cell Line
  • Cell Membrane / enzymology
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Glycoproteins / metabolism*
  • Host-Pathogen Interactions*
  • Immunoblotting
  • Immunoprecipitation
  • Microscopy, Fluorescence
  • Neuraminidase / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protozoan Proteins / metabolism*
  • Rats
  • Trypanosoma cruzi / pathogenicity*
  • Two-Hybrid System Techniques


  • Glycoproteins
  • Protozoan Proteins
  • Cyclic AMP-Dependent Protein Kinases
  • trans-sialidase
  • Neuraminidase