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UID:20250507T053554EDT-1633xvKH6m@132.216.98.100
DTSTAMP:20250507T093554Z
DESCRIPTION:'Evolutionary rewiring of a bacterial signaling pathway'\n\nDan
 nie Durand\, Carnegie Mellon University\n	Tuesday October 9\, 12-1pm\n	McInt
 yre Building\, Room 1027\n\nSurvival in a changing world requires flexible
  signaling circuitry that can evolve in response to new environmental chal
 lenges. The Firmicute sporulation initiation (Spo0) pathway is a compellin
 g example of signaling circuitry that has changed over evolution. In Clost
 ridium acetobutylicum\, the signal is passed directly from a sensor kinase
  to the activator of sporulation. In Bacillus subtilis\, the signal is tra
 nsmitted from the sensor through two intermediate proteins to the activato
 r\, in a so-called phosphorelay. What was the ancestral pathway architectu
 re and how did evolution produce different circuit diagrams that control t
 he same phenotype?\n\nThe current view is that the ancestral Spo0 pathway 
 had the simpler two-protein architecture and that the four-protein phospho
 relay arose later in Bacilli. Our analysis of 84 Firmicutes genomes challe
 nges this hypothesis. We identified phosphorelays in many Clostridia\, as 
 well as Bacilli\, consistent with a model wherein the ancestral pathway wa
 s a phosphorelay and the present-day two-protein pathway arose later throu
 gh evolutionary rewiring. This model is further supported by in vitro phos
 photransfer experiments in which replacing any Bacillar phosphorelay prote
 in with the corresponding protein from a Clostridial phosphorelay results 
 in a functional pathway. This implies that the molecular recognition signa
 ls that control interaction specificity in the Spo0 phosphorelay have not 
 changed in the 2.7 billion years since the divergence of the Bacilli and t
 he Clostridia. Finally\, the phylogenetic distribution of two-protein Spo0
  pathways is patchy\, suggesting multiple\, independent instances of rewir
 ing from a four-protein phosphorelay to a two-protein pathway.\n
DTSTART:20181009T160000Z
DTEND:20181009T170000Z
LOCATION:Room 1027\, McIntyre Medical Building\, CA\, QC\, Montreal\, H3G 1
 Y6\, 3655 promenade Sir William Osler
SUMMARY:Seminar Series in Quantitative Life Sciences and Medicine
URL:/qls/channels/event/seminar-series-quantitative-li
 fe-sciences-and-medicine-290176
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