Document Detail

A RelA-dependent two-tiered regulated proteolysis cascade controls synthesis of a contact-dependent intercellular signal in Myxococcus xanthus.
MedLine Citation:
PMID:  22404381     Owner:  NLM     Status:  Publisher    
Proteolytic cleavage of precursor proteins to generate intercellular signals is a common mechanism in all cells. In Myxococcus xanthus the contact-dependent intercellular C-signal is a 17 kDa protein (p17) generated by proteolytic cleavage of the 25 kDa csgA protein (p25), and is essential for starvation-induced fruiting body formation. p25 accumulates in the outer membrane and PopC, the protease that cleaves p25, in the cytoplasm of vegetative cells. PopC is secreted in response to starvation, therefore, restricting p25 cleavage to starving cells. We focused on identifying proteins critical for PopC secretion in response to starvation. PopC secretion depends on the (p)ppGpp synthase RelA and the stringent response, and is regulated post-translationally. PopD, which is encoded in an operon with PopC, forms a soluble complex with PopC and inhibits PopC secretion whereas the integral membrane AAA+ protease FtsH(D) is required for PopC secretion. Biochemical and genetic evidence suggest that in response to starvation, RelA is activated and induces the degradation of PopD thereby releasing pre-formed PopC for secretion and that FtsH(D) is important for PopD degradation. Hence, regulated PopC secretion depends on regulated proteolysis. Accordingly, p17 synthesis depends on a proteolytic cascade including FtsH(D) -dependent degradation of PopD and PopC-dependent cleavage of p25.
Anna Konovalova; Stephanie Löbach; Lotte Søgaard-Andersen
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-3-8
Journal Detail:
Title:  Molecular microbiology     Volume:  -     ISSN:  1365-2958     ISO Abbreviation:  -     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-3-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 Blackwell Publishing Ltd.
Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043 Marburg, Germany.
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