FFAT motif phosphorylation controls formation and lipid transfer function of inter-organelle contacts.
Fiche publication
Date publication
octobre 2020
Journal
The EMBO journal
Auteurs
Membres identifiés du Cancéropôle Est :
Dr ALPY Fabien, Pr CAVARELLI Jean, Dr TOMASETTO Catherine, Mr EBERLING Pascal , Dr NOMINE Yves, Mr RUFFENACH Frank
Tous les auteurs :
Di Mattia T, Martinet A, Ikhlef S, McEwen AG, Nominé Y, Wendling C, Poussin-Courmontagne P, Voilquin L, Eberling P, Ruffenach F, Cavarelli J, Slee J, Levine TP, Drin G, Tomasetto C, Alpy F
Lien Pubmed
Résumé
Organelles are physically connected in membrane contact sites. The endoplasmic reticulum possesses three major receptors, VAP-A, VAP-B, and MOSPD2, which interact with proteins at the surface of other organelles to build contacts. VAP-A, VAP-B, and MOSPD2 contain an MSP domain, which binds a motif named FFAT (two phenylalanines in an acidic tract). In this study, we identified a non-conventional FFAT motif where a conserved acidic residue is replaced by a serine/threonine. We show that phosphorylation of this serine/threonine is critical for non-conventional FFAT motifs (named Phospho-FFAT) to be recognized by the MSP domain. Moreover, structural analyses of the MSP domain alone or in complex with conventional and Phospho-FFAT peptides revealed new mechanisms of interaction. Based on these new insights, we produced a novel prediction algorithm, which expands the repertoire of candidate proteins with a Phospho-FFAT that are able to create membrane contact sites. Using a prototypical tethering complex made by STARD3 and VAP, we showed that phosphorylation is instrumental for the formation of ER-endosome contacts, and their sterol transfer function. This study reveals that phosphorylation acts as a general switch for inter-organelle contacts.
Mots clés
cholesterol, inter-organelle contact, lipid transfer protein, regulation, small linear motif
Référence
EMBO J. 2020 Oct 30;:e104369