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

https://www.ncbi.nlm.nih.gov/pubmed/33124732

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.