BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//SFP Alpes - ECPv6.17.5.1//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-ORIGINAL-URL:https://sfp-alpes.fr
X-WR-CALDESC:Évènements pour SFP Alpes
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:Europe/Paris
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20250330T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20251026T010000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20260329T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20261025T010000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20270328T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20271031T010000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20261013T140000
DTEND;TZID=Europe/Paris:20261013T160000
DTSTAMP:20260925T153332Z
CREATED:20260925T153332Z
LAST-MODIFIED:20260925T153332Z
UID:10000270-1791900000-1791907200@sfp-alpes.fr
SUMMARY:Soutenance de Thèse par Maria VAL PEVIDA (CEA-Irig/IBS)
DESCRIPTION:Structural study of NADPH oxidase complex NOX1 by cryo-electron microscopy\nRésumé : \nMembrane proteins (MPs) constitute a major class of pharmaceutical targets due to their central roles in essential physiological processes. Among them\, NADPH oxidases (NOX) comprise a family of transmembrane enzymes involved in numerous crucial cellular functions — including host defence\, hormone synthesis\, vascular tone regulation\, and equilibrium — through the regulated production of reactive oxygen species (ROS). NOX1\, one of the human NOX isoforms\, is predominantly expressed in the intestinal epithelium\, where it forms a heterodimeric complex with p22phox in the membrane. Dysregulation of NOX1 activity\, often arising from genetic mutations\, has been associated with early-onset colorectal cancer and inflammatory bowel disease (IBD). Elucidating the three-dimensional structures of MPs and their mechanistic properties is essential to accelerate structure-based drug design strategies. Cryo-electron microscopy (cryo-EM) has become a powerful technique for resolving MPs structures at atomic resolutions. However\, structural determination of small MPs (<100 kDa) remains challenging due to their low expression levels\, low signal-to-noise ratios\, dependence on detergent solubilisation\, and intrinsic conformational flexibility\, all which complicating particle alignment and high-resolution structure reconstruction. To overcome these limitations\, antigen-binding fragments (Fabs) are frequently employed as fiducials to increase particle size and stabilise specific conformations by binding to defined epitopes. \nIn this thesis\, a lentiviral-based expression system was developed for the overexpression of the NOX1/p22phox complex in HEK293 T-Rex cells. Initial attempts to determine the structure of wild-type NOX1 were unsuccessful due to low production yield and the small size of the complex\, compounded by the lack of a commercially available monoclonal antibody targeting NOX1. To overcome these limitations\, co-expression with the EROS chaperone\, combined with the engineering of a NOX1 mutant\, named NOX12\, enabled improved production. This mutant incorporates modifications in extracellular loops to allow specific recognition by the anti-NOX2 Fab7D5. This strategy increased particle size\, allowing particle alignment and facilitating structural determination of the complex by cryo-EM. High-resolution structure of the core of NOX12 in complex with p22phox and Fab7D5 was determined at an overall resolution of 2.8 Å. In addition\, the structure of the NOX12/p22phox in complex with EROS and Fab7D5 was resolved at an overall resolution of 3.2 Å. This structure revealed a previously uncharacterised interaction mode between EROS and the catalytic subunit. Furthermore\, the structural framework enabled analysis of disease-associated mutations in NOX1 and provided insights into oxygen access pathways. \nThis work provides the first structural insights into NOX1 isoform in complex with its partner p22phox and together with the EROS chaperone\, establishing a framework for understanding its stabilisation and maturation. In addition\, the successful implementation of protein epitope engineering highlights a broadly applicable strategy for studying other NOX isoforms that lack specific antibodies\, in both resting and activated states\, thereby enabling cryo-EM characterisation across this family of MPs. Further studies will be required to elucidate the detailed molecular mechanisms underlying NOX1 activation. ​​​​ \n_ \n\n\nLes séminaires et soutenances sont ouverts à tous\, notez toutefois que l’accès au campus EPN nécessite un avis de rendez-vous. Merci de remplir ce formulaire  et de l’adresser\, plus de 48h à l’avance\, à ce contact.\nPensez à vous munir d’une pièce d’identité le jour de votre visite.
URL:https://sfp-alpes.fr/event/soutenance-de-these-par-maria-val-pevida-cea-irig-ibs/
LOCATION:IBS – Salle des séminaires\, IBS 71 avenue des Martyrs\, Grenoble\, 38042\, France
CATEGORIES:Soutenance,Soutenance de Thèse
ORGANIZER;CN="IRIG - CEA":MAILTO:irig.communication@cea.fr
END:VEVENT
END:VCALENDAR