Interplay between Rab11, Rab14 and FIP2 in Chlamydia trachomatis-infected cells.

LEIVA N; CAPMANY A; GAMBARTE J; DAMIANI MT

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

The intracellular pathogen, Chlamydia trachomati, replicates within a special compartment limited by membranes (called ?inclusion?) and takes advantage of host vesicular transport for its own benefit. Rab GTPases are key regulatory proteins of intracellular trafficking. We have demonstrated that Rab11, Rab14 and Rab11-Interacting Protein 2 (FIP2) are recruited to chlamydial inclusions and, are necessary for bacterial multiplication. Recently, it has been described that FIP2 encompasses, at its C-terminus, a Rab Binding Domain (RBD) that interacts with both, Rab11 and Rab14. The aim of this study was to assess the interplay between these three host proteins in infected cells. The degree of colocalization at the chlamydial inclusion membrane was measured by quantitative confocal microscopy. Manders´ and Pearson´s coefficients indicated almost complete colocalization between these proteins, even after Golgi disorganization or depolymerization of microtubules. Overexpression of the Rab11 GDP-bound mutant (Rab11-S25N) decreased the recruitment of FIP2, whereas the overexpression of the FIP2 mutant lacking the RBD (FIP2 C2 RBD) did not affect Rab11 association with chlamydial inclusions. On the contrary, the silencing of FIP2 diminished the binding of Rab14. These results might suggest that FIP2 coordinates the sequential recruitment of Rab11 and Rab14 to chlamydial inclusions.