Phytopathogen type III effectors as probes of biological systems

Phytopathogen type III effectors as probes of biological systems

Bacterial phytopathogens utilize a myriad of virulence factors to modulate their plant hosts in order to promote successful pathogenesis. One potent virulence strategy is to inject these virulence proteins into plant cells via the type III secretion system. Characterizing the host targets and the molecular mechanisms of type III secreted proteins, known as effectors, has illuminated our underst...

Pseudomonas type-III effectors

Type III effectors in action

The way proteins are translocated across the peroxisomal membrane is poorly understood. Though the existence of transient pores in the membrane had been proposed, their identification had remained elusive until now. In a new study, Erdmann and colleagues tagged peroxisomal matrix protein receptor Pex5p and isolated three Pex5p-containing complexes from yeast peroxisomal membranes. These three c...

New effects of type III effectors.

The enzymatic activities and/or targets of four type III effector proteins from plant pathogens have been reported in a flurry of new papers. In this issue, XopD is shown to remove SUMO groups from host cell proteins, while in previous issues of Molecular Microbiology, HopPtoD2 was shown to function as a tyrosine phosphatase and AvrRpt2 as probably a cysteine protease that targets the host RIN4...

Biochemical functions of Yersinia type III effectors.

Yersinia uses a type III secretion system (TTSS) to deliver six effector proteins into host cells. These six proteins harbor distinct activities that are mimicries of host functions but often have acquired unique biochemical features. The host targets for these effectors appear to be limited to a few key signaling components such as G proteins and kinases, whereas their models of action are div...