Localization and dynamics of the succinoglycan translocon in Sinorhizobium meliloti cells

RIVERO MR; MEDEOT D; CONTRERAS-MOREIRA B; LIAUDAT JP; FERRARI W; ROSSI F; FISCHER S; BECKER A; JOFRE E

Sevilla

Congreso; II IBEMPA Conferencia Iberoamericana de interacciones beneficiosas microorganismo-planta-ambiente. XXVI Reunion Latinoamericana de rizobiología; 2013

Spanish Society of Nitrogen Fixation (SEFIN) Latin American Society Rhizobiology (ALAR) University of Seville

A Wzy-dependent like pathway , which includes the participation of ExoPTQF proteins, has been suggested to be involved in the polymerization of exopolysaccharide I (EPS I) of S.meliloti. However , the final steps of this process are poorly understood. Recently , by cellular fractionation and immunoblot, our group has evidenced a PCP2a family protein, ExoP , located in the inner membrane and its pivotal role in EPS I synthesis has been established. Here, we show preliminary results about the role of ExoF in this process and its potential interactions with ExoP . By bioinformatics analysis, we identified ExoF as OMA family member located in the outer membrane. Furthermore, generation of nonpolar exoF mutant resulted in a nonproducing EPS I phenotype. Confocal laser microscopy analysis of cells expressing ExoF-mCherry- and eGFP-ExoP tagged proteins, revealed that these proteins are highly dynamics during the exponential phase of growth. However , when the growth rate decreases, both proteins localize at cell poles and this moment is coincident with the beginning of EPS I export. Based on all these data, we postulate that ExoP and ExoF interact each other to form a protein complex that allows the assemblage and translocation of EPS I