CROSS TALK BETWEEN SIGNAL TRANSDUCTION SYSTEMS CONTRIBUTES TO PNEUMOCOCCAL PATHOGENESIS.

ECHENIQUE J

Cordoba

Simposio; Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2016

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

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 tothe 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 survivalmechanism known as acid tolerance response (ATR). In this work, we report an alternative activation pathway of ComE. Weperformed molecular, biochemical and functional assays to characterize another signal transduction system that activates ComE bycrosstalk phosphorylation. We also found that this new signaling pathway regulates autolysis and ATR under acidic stress, and thatthese mechanisms modulate the intracellular survival of S. pneumoniae in pneumocytes. We propose that the convergence of thesesignal transduction systems represents a key pathway in the global stress response and contributes to the pneumococcal pathogenesis.