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DTSTAMP:20260424T123717Z
UID:5a0bfdcdc82f3053736060@ist.ac.at
DTSTART:20171123T140000
DTEND:20171123T150000
DESCRIPTION:Speaker: Harald Hofbauer\nhosted by Harald Janovjak\nAbstract: 
 A key decision in cellular physiology is the decision between membrane bio
 genesis and lipid storage. The regulatory pathways underlying these cellul
 ar processes must be carefully coordinated and tightly controlled. The lip
 id metabolite phosphatidic acid (PA) represents the branch point between g
 lycerophospholipid production for cell proliferation and triacylglycerol s
 ynthesis for fat storage1. PA molecules have a high metabolic turnover and
  also serve as critical signaling lipids. In the bakers yeast Saccharomyce
 s cerevisiae\, the PA level of the ER is constantly monitored by the solub
 le repressor Opi1 via its polybasic PA binding domain to control the trans
 criptional program of glycerophospholipid biosynthesis2. However\, mechani
 stic details on the binding mode of Opi1 remain yet elusive.We here identi
 fied and characterized an amphipathic helix (AH) in Opi1s PA binding domai
 n that is additionally capable for acyl chain sensing of the lipid bilayer
  after initial electrostatic membrane recruitment. Using a combined in viv
 o\, in vitro and in silico approach\, we provide evidence that directed tu
 ning of the helix affects its membrane binding selectivity as well as bind
 ing strength. Thus\, the AH enables specific membrane recognition that goe
 s beyond sensing of total PA levels and allows Opi1 to rapidly respond on 
 various derailments of membrane lipid homeostasis by directly adjusting gl
 ycerophospholipid metabolism.Taken together\, our data reveal novel insigh
 ts into fundamental aspects of membrane sensing by using the AH of Opi1 as
  show box for highly selective target membrane recognition. These findings
  potentially help to generate fine-tuned membrane sensors as well as synth
 etically optimized antimicrobial peptides in future projects.References:1.
 Henry\, S. A.\, Kohlwein\, S. D. & Carman\, G. M. Metabolism and Regulatio
 n of Glycerolipids in the Yeast Saccharomyces cerevisiae. Genetics 190\, 3
 17349 (2012).2.Loewen\, C. J. R. et al. Phospholipid metabolism regulated 
 by a transcription factor sensing phosphatidic acid. Science 304\, 16447 (
 2004).
LOCATION:Mondi Seminar Room 2\, Central Building\, ISTA
ORGANIZER:amally@ist.ac.at
SUMMARY:Harald Hofbauer: Selective membrane sensing via an amphipathic heli
 x in Opi1 to control lipid metabolism in yeast
URL:https://talks-calendar.ista.ac.at/events/960
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