Adhesion Of Trypanosoma Cruzi Trypomastigotes To Fibronectin Or Laminin Modifies Tubulin And Paraflagellar Rod Protein Phosphorylation

Adhesion of Trypanosoma cruzi Trypomastigotes to
Fibronectin or Laminin Modifies Tubulin and
Paraflagellar Rod Protein Phosphorylation
Eliciane C. Mattos, Robert I. Schumacher, Walter Colli, Maria Julia M. Alves*
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Departamento de Bioquımica, Instituto de Quımica, Universidade de Sao Paulo, Sao Paulo, Brazil

Abstract
Background: The unicellular parasite Trypanosoma cruzi is thecausative agent of Chagas disease in humans. Adherence of
the infective stage to elements of the extracellular matrix (ECM), as laminin and fibronectin, is an essential step in host cell
invasion. Although members of the gp85/TS, as Tc85, were identified as laminin and fibronectin ligands, the signaling
events triggered on the parasite upon binding to these molecules are largely unexplored.Methodology/Principal Findings: Viable infective parasites were incubated with laminin, fibronectin or bovine serum
albumin for different periods of time and the proteins were separated by bidimensional gels. The phosphoproteins were
envisaged by specific staining and the spots showing phosphorylation levels significantly different from the control were
excised and identified by MS/MS. Theresults of interest were confirmed by immunoblotting or immunoprecipitation and
the localization of proteins in the parasite was determined by immunofluorescence. Using a host cell-free system, our data
indicate that the phosphorylation contents of T. cruzi proteins encompassing different cellular functions are modified upon
incubation of the parasite with fibronectin or laminin.Conclusions/Significance: Herein it is shown, for the first time, that paraflagellar rod proteins and a-tubulin, major structural
elements of the parasite cytoskeleton, are predominantly dephosphorylated during the process, probably involving the
ERK1/2 pathway. It is well established that T. cruzi binds to ECM elements during the cell infection process. The fact that
laminin and fibronectin induce predominantlydephosphorylation of the main cytoskeletal proteins of the parasite suggests
a possible correlation between cytoskeletal modifications and the ability of the parasite to internalize into host cells.
Citation: Mattos EC, Schumacher RI, Colli W, Alves MJM (2012) Adhesion of Trypanosoma cruzi Trypomastigotes to Fibronectin or Laminin Modifies Tubulin and
Paraflagellar Rod Protein Phosphorylation.PLoS ONE 7(10): e46767. doi:10.1371/journal.pone.0046767
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Editor: Roger Chammas, Faculdade de Medicina, Universidade de Sao Paulo, Brazil
Received April 20, 2012; Accepted September 5, 2012; Published October 4, 2012
Copyright: ß 2012 Mattos et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use,distribution, and reproduction in any medium, provided the original author and source are credited.
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Funding: This work was funded by research grants from Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP # 2009/52646-6 to MJMA) and from
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Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (CNPq) to MJMA and WC (#303539/2005-4). ECM is a graduate fellow from CNPq. Thefunders
had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: mjmalves@iq.usp.br

adequately in order to survive. Among the possible responses,
post-translational modification of proteins appears to be operative.
Post-translationalmodifications of proteins provide an efficient
tool to regulate the activity of key proteins, with reversible
phosphorylation being a frequent one. The large amount of
kinases (190 protein kinase genes) and phosphatases (86 protein
phosphatase genes) in the T. cruzi genome suggests a major role of
the protein phosphorylation cycle in signaling events [2,3].
Accordingly, from the 119 proteins with...