Control of natural transformation in salivarius Streptococci through specific degradation of ?X by the MecA-ClpCP protease complex.
Ontology highlight
ABSTRACT: Competence for natural DNA transformation is a tightly controlled developmental process in streptococci. In mutans and salivarius species, the abundance of the central competence regulator ?(X) is regulated at two levels: transcriptional, by the ComRS signaling system via the ?(X)/ComX/SigX-inducing peptide (XIP), and posttranscriptional, by the adaptor protein MecA and its associated Clp ATPase, ClpC. In this study, we further investigated the mechanism and function of the MecA-ClpC control system in the salivarius species Streptococcus thermophilus. Using in vitro approaches, we showed that MecA specifically interacts with both ?(X) and ClpC, suggesting the formation of a ternary ?(X)-MecA-ClpC complex. Moreover, we demonstrated that MecA ultimately targets ?(X) for its degradation by the ClpCP protease in an ATP-dependent manner. We also identify a short sequence (18 amino acids) in the N-terminal domain of ?(X) as essential for the interaction with MecA and subsequent ?(X) degradation. Finally, increased transformability of a MecA-deficient strain in the presence of subinducing XIP concentrations suggests that the MecA-ClpCP proteolytic complex acts as an additional locking device to prevent competence under inappropriate conditions. A model of the interplay between ComRS and MecA-ClpCP in the control of ?(X) activity is proposed.
SUBMITTER: Wahl A
PROVIDER: S-EPMC4135673 | biostudies-literature | 2014 Aug
REPOSITORIES: biostudies-literature
ACCESS DATA