Crosstalk between signal transduction systems in Streptococcus pneumoniae.

ECHENIQUE J

Rosario

Congreso; XXIII Congreso Latinoamericano de Microbiologia; 2016

Asociación Latinoamericana de Microbiología

CROSS TALK BETWEEN SIGNAL TRANSDUCTION SYSTEMS CONTRIBUTES TO PNEUMOCOCCAL PATHOGENESIS.Echenique J.Dpto de Bioquimica Clinica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. CIBICI-CONICET.E-mail:jeche@fcq.unc.edu.arLiving cells modulate their gene expression patterns in response to environmental cuesto adapt and to survive. In bacteria, extracellular signals are transduced into the cells mainly by signal transduction mechanisms named as two-component systems (TCS). Streptococcus pneumoniae, a significant bacterial human pathogen, induce competence by a quorum-sensing mechanism associated to the ComDE TCS under slight alkaline conditions. We previously described thatacidic stressinduces two types of cellular response in S. pneumoniae, either by triggering cell death by autolysis (and releasing the pneumolysincytotoxin), or by inducing a survival mechanism known as acid tolerance response (ATR). In this work, we report an alternative activation pathway of ComE. We performed molecular, biochemical and functional assays to characterize another signal transduction system that activates ComE by crosstalk phosphorylation. We also found that this new signaling pathway regulates autolysis and ATR under acidic stress, and that these mechanisms modulate the intracellular survival of S. pneumoniae in pneumocytes. We propose that the convergence of these signal transduction systems represents a key pathway in the global stress response and contributes to the pneumococcal pathogenesis.