biostudies-literatureEnde RJNational Institute of Allergy and Infectious Diseasese74535https://www.ebi.ac.uk/biostudies/studies/S-EPMC9286742biostudies-literatureUnknown11Membrane contact sites (MCS) are crucial for nonvesicular trafficking-based interorganelle communication. Endoplasmic reticulum (ER)-organelle tethering occurs in part through the interaction of the ER resident protein VAP with FFAT motif-containing proteins. FFAT motifs are characterized by a seven amino acidic core surrounded by acid tracks. We have previously shown that the human intracellular bacterial pathogen <i>Chlamydia trachomatis</i> establishes MCS between its vacuole (the inclusion) and the ER through expression of a bacterial tether, IncV, displaying molecular mimicry of eukaryotic FFAT motif cores. Here, we show that multiple layers of host cell kinase-mediated phosphorylation events govern the assembly of the IncV-VAP tethering complex and the formation of ER-Inclusion MCS. eLifePhosphoregulation accommodates Type III secretion and assembly of a tether of ER-<i>Chlamydia</i> inclusion membrane contact sites.PMC9286742AI162758AI007046AI136283AI141841AI101441AI060767AI166237Coppens IDerre IMurray RLD'Spain SKEnde RJfalsePhosphoregulation accommodates Type III secretion and assembly of a tether of ER-<i>Chlamydia</i> inclusion membrane contact sites.Membrane contact sites (MCS) are crucial for nonvesicular trafficking-based interorganelle communication. Endoplasmic reticulum (ER)-organelle tethering occurs in part through the interaction of the ER resident protein VAP with FFAT motif-containing proteins. FFAT motifs are characterized by a seven amino acidic core surrounded by acid tracks. We have previously shown that the human intracellular bacterial pathogen <i>Chlamydia trachomatis</i> establishes MCS between its vacuole (the inclusion) and the ER through expression of a bacterial tether, IncV, displaying molecular mimicry of eukaryotic FFAT motif cores. Here, we show that multiple layers of host cell kinase-mediated phosphorylation events govern the assembly of the IncV-VAP tethering complex and the formation of ER-Inclusion MCS. 2022-01-01T00:00:00Z2022 Jul2025-04-04T07:11:00.179Z2025-02-19T03:22:14.144ZS-EPMC92867423583822810.7554/eLife.74535