biostudies-literatureCardoen BNatural Sciences and Engineering Research Council of CanadaCanadian Institutes of Health ResearchCIHRe202206109https://www.ebi.ac.uk/biostudies/studies/S-EPMC10638097biostudies-literatureUnknown223(1)Identification and morphological analysis of mitochondria-ER contacts (MERCs) by fluorescent microscopy is limited by subpixel resolution interorganelle distances. Here, the membrane contact site (MCS) detection algorithm, MCS-DETECT, reconstructs subpixel resolution MERCs from 3D super-resolution image volumes. MCS-DETECT shows that elongated ribosome-studded riboMERCs, present in HT-1080 but not COS-7 cells, are morphologically distinct from smaller smooth contacts and larger contacts induced by mitochondria-ER linker expression in COS-7 cells. RiboMERC formation is associated with increased mitochondrial potential, reduced in Gp78 knockout HT-1080 cells and induced by Gp78 ubiquitin ligase activity in COS-7 and HeLa cells. Knockdown of riboMERC tether RRBP1 eliminates riboMERCs in both The Journal of cell biologyMembrane contact site detection (MCS-DETECT) reveals dual control of rough mitochondria-ER contacts.PMC10638097RGPIN-2019-05179AWD-022443RGPIN-2018-03727RGPIN-2020-06752COP-137359PJT-148698COP-143083Alan PTiliakou EVandevoorde KROrtiz-Silva MVogl AWGao GCardoen BHamarneh GNabi IRLiu WfalseMembrane contact site detection (MCS-DETECT) reveals dual control of rough mitochondria-ER contacts.Identification and morphological analysis of mitochondria-ER contacts (MERCs) by fluorescent microscopy is limited by subpixel resolution interorganelle distances. Here, the membrane contact site (MCS) detection algorithm, MCS-DETECT, reconstructs subpixel resolution MERCs from 3D super-resolution image volumes. MCS-DETECT shows that elongated ribosome-studded riboMERCs, present in HT-1080 but not COS-7 cells, are morphologically distinct from smaller smooth contacts and larger contacts induced by mitochondria-ER linker expression in COS-7 cells. RiboMERC formation is associated with increased mitochondrial potential, reduced in Gp78 knockout HT-1080 cells and induced by Gp78 ubiquitin ligase activity in COS-7 and HeLa cells. Knockdown of riboMERC tether RRBP1 eliminates riboMERCs in both 2024-01-01T00:00:00Z2024 Jan2026-05-28T22:30:38.755Z2025-02-19T00:01:40.346ZS-EPMC106380973794812610.1083/jcb.202206109