Download Séminaire de l`IPBS Axel Magalon Laboratoire de Chimie

Séminaire de l’IPBS
Axel Magalon
Laboratoire de Chimie Bactérienne, UMR 7283, Marseille
Mardi 26 janvier 2016 à 11 h
Salle des séminaires
Dynamic subcellular distribution is key to control bacterial
respiration
Respiration is an essential process for most living organisms sustained by multisubunit complexes anchored in
the lipid bilayer. The basic principle of respiration applies to the respiratory electron transfer chains of
eukaryotes and prokaryotes. Plasticity is a hallmark of the respiratory process. In eukaryotes, mitochondria are
dynamic compartments fine-tuning their activity in response to changes in nutrient availability and oxygen
concentrations through a plastic organization of the respiratory complexes in the membrane. Similarly,
prokaryotes are characterized by the coexistence of several complexes both at the electron input and output
leading to multiple electron transfer routes. Such a metabolic flexibility accounts for colonization of multiple
environments and adaptation to environmental changes such as the ones encountered by pathogens during
interaction with their hosts. An immediate question concerns the cellular organization of respiration in living
organisms i.e. how are distributed the complexes across the membrane? Is there a dynamic distribution?
Furthermore, does such organization have functional implications?
Through the use of fluorescent protein tagging, distribution at the single-cell level of the nitrate reductase from
the commensal gut bacterium E. coli was studied. Apart from observing a submicrometric localization of the
complex at the bacterial cell poles, its distribution within the cytoplasmic membrane is strongly influenced by
environmental signals, that is, in response to the metabolic demand. We provide here the identification of
unprecedented polar cues and describe the functional implications of such spatio-temporal regulation. How
spatio-temporal regulation on timescales of few tens of minutes may significantly influence the optimum
performance of the bacterial cell will be discussed in the general context of bacterial respiration but also during
intestinal inflammation.
Relevant publications
 Alberge et al. (2015) Dynamic subcellular localization of a respiratory complex controls bacterial respiration.
Elife doi: 10.7554/eLife.05357
 Arnoux et al. (2015) Sulphur shuttling across a chaperone during molybdenum cofactor maturation. Nat
Commun 6:6148
 Magalon et al. (2012) Supramolecular organization in prokaryotic respiratory systems. Adv Microb Physiol
61:217-66
 Arias-Cartin et al. (2011) Cardiolipin-based respiratory complex activation in bacteria. Proc Natl Acad Sci USA
108(19):7781-6
 Magalon et al. (2011) Molybdenum enzymes in bacteria and their maturation. Coord Chem Rev 255 (910):1159-78
Contact : [email protected]
Pré-inscription obligatoire 48h à l’avance à dé[email protected]
Prière de vous présenter muni d’une pièce d’identité
Campus CNRS, 205 route de Narbonne - TOULOUSE