FFAT motif phosphorylation controls formation and lipid transfer function of inter‐organelle contacts

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

BRP peptide detection in human CSF (mass spectrometry data)

Targeted metabolomics measurements were performed using an Agilent Q-TOF LC–MS instrument to verify that BRP is endogenously secreted at detectable levels in humans. We quantitated the m/z intensity of the endogenous peptide in human cerebrospinal fluid (CSF) relative to the synthesized peptide. The raw mass spectrometry (MS1 spectra) data are deposited as Agilent .d file for the synthesized peptide (BRP_amide.d) and the human CSF preparation (humanCSFprep.d). Quantification of BRP was done by manual integration (AUC) in Agilent Mass Hunter software and compared to a standard curve to estimate the CSF concentration. The data demonstrates the detection of endogenous amidated BRP in human CSF at 24 minutes at levels around 3 nM

BRP peptide detection in human CSF (mass spectrometry data)

Targeted metabolomics measurements were performed using an Agilent Q-TOF LC–MS instrument to verify that BRP is endogenously secreted at detectable levels in humans. We quantitated the m/z intensity of the endogenous peptide in human cerebrospinal fluid (CSF) relative to the synthesized peptide. The raw mass spectrometry (MS1 spectra) data are deposited as Agilent .d file for the synthesized peptide (BRP_amide.d) and the human CSF preparation (humanCSFprep.d). Quantification of BRP was done by manual integration (AUC) in Agilent Mass Hunter software and compared to a standard curve to estimate the CSF concentration. The data demonstrates the detection of endogenous amidated BRP in human CSF at 24 minutes at levels around 3 nM.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV