Pseudomonas aeruginosa is the most common gram-negative pathogen causing pneumonia in immunocompromised patients. Acute lung injury induced by bacterial exoproducts is associated with a poor outcome in P. aeruginosa pneumonia. The major pathogenic toxins among the exoproducts of P. aeruginosa and the mechanism by which they cause acute lung injury have been investigated: exoenzyme S and co-regu...

-Mechanical stress induces a variety of hypertrophic responses, such as activation of protein kinases, reprogramming of gene expression, and an increase in protein synthesis. In the present study, to elucidate how mechanical stress induces such events, we examined the role of Rho family small GTP-binding proteins (G proteins) in mechanical stress-induced cardiac hypertrophy. Treatment of neonat...

Through production and sensing of small signal molecules, quorum sensing (QS) enables bacteria to detect changes in their density and regulate their functions accordingly. QS systems are tremendously diverse in terms of their specific sensory components, the biochemical and transport properties of signaling molecules, their target functions and the context in which QS-mediated functions are act...

The aim of this study was to evaluate the prevalence of some virulence genes among 202 Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients (n=42) and non-CF in-patients (n=160) and to analyze the values according to the patient groups, infection localization and antimicrobial resistance. The following frequencies in all studied strains were established: algD (encoding GDP-mannose...

14-3-3 proteins are phosphoserine/phosphothreonine-recognizing adapter proteins that regulate the activity of a vast array of targets. There are also examples of 14-3-3 proteins binding their targets via unphosphorylated motifs. Here we present a structural and biological investigation of the phosphorylation-independent interaction between 14-3-3 and exoenzyme S (ExoS), an ADP-ribosyltransferas...

Pseudomonas aeruginosa exoenzyme S (ExoS) is a type III secretion (TTS) effector, which includes both a GTPase-activating protein (GAP) activity toward the Rho family of low-molecular-weight G (LMWG) proteins and an ADP-ribosyltransferase (ADPRT) activity that targets LMWG proteins in the Ras, Rab, and Rho families. The coordinate function of both activities of ExoS in J774A.1 macrophages was a...

Type III-delivered exoenzyme S (ExoS) preferentially ADP-ribosylated membrane-associated His(6)HRas, relative to its cytosolic derivative His(6)HRas Delta CAAX. This indicates that the subcellular protein distribution contributes to in vivo ADP-ribosylation by ExoS.

The small GTPase Rho acts on two effectors, ROCK and mDia1, and induces stress fibers and focal adhesions. However, how ROCK and mDia1 individually regulate signals and dynamics of these structures remains unknown. We stimulated serum-starved Swiss 3T3 fibroblasts with LPA and compared the effects of C3 exoenzyme, a Rho inhibitor, with those of Y-27632, a ROCK inhibitor. Y-27632 treatment suppr...

Activation of the T lymphocyte induces dramatic cytoskeletal changes, and there is increasing evidence that disruption of the cytoskeleton inhibits early and late events of T cell signal transduction. However, relatively little is known about the signaling molecules involved in activation-induced cytoskeletal rearrangement. The rho family of small GTP-binding proteins, which include rho, rac, a...

The identity of G proteins mediating CCK-stimulated phospholipase D (PLD) activity was determined in intestinal smooth muscle cells. CCK-8 activated G(q/11), G(13), and G(12), and the monomeric G proteins Ras-homology protein (RhoA) and ADP ribosylation factor (ARF). Activation of RhoA, but not ARF, was mediated by G(13) and inhibited by Galpha(13) antibody. CCK-stimulated PLD activity was part...