PDZD8-FKBP8 tethering complex at ER-mitochondria contact sites regulates mitochondrial complexity.
Koki NakamuraSaeko Aoyama-IshiwatariTakahiro NagaoMohammadreza PaaranChristopher J ObaraYui Sakurai-SaitoJake JohnstonYudan DuShogo SugaMasafumi TsuboiMakoto NakakidoKouhei TsumotoYusuke KishiYukiko GotohChulhwan KwakHyun-Woo RheeJeong Kon SeoHidetaka KosakoClint PotterBridget CarragherJennifer Lippincott-SchwartzFranck PolleuxYusuke HirabayashiPublished in: bioRxiv : the preprint server for biology (2024)
Mitochondria-ER membrane contact sites (MERCS) represent a fundamental ultrastructural feature underlying unique biochemistry and physiology in eukaryotic cells. The ER protein PDZD8 is required for the formation of MERCS in many cell types, however, its tethering partner on the outer mitochondrial membrane (OMM) is currently unknown. Here we identified the OMM protein FKBP8 as the tethering partner of PDZD8 using a combination of unbiased proximity proteomics, CRISPR-Cas9 endogenous protein tagging, Cryo-Electron Microscopy (Cryo-EM) tomography, and correlative light-EM (CLEM). Single molecule tracking revealed highly dynamic diffusion properties of PDZD8 along the ER membrane with significant pauses and capture at MERCS. Overexpression of FKBP8 was sufficient to narrow the ER-OMM distance, whereas independent versus combined deletions of these two proteins demonstrated their interdependence for MERCS formation. Furthermore, PDZD8 enhances mitochondrial complexity in a FKBP8-dependent manner. Our results identify a novel ER-mitochondria tethering complex that regulates mitochondrial morphology in mammalian cells.
Keyphrases
- endoplasmic reticulum
- electron microscopy
- estrogen receptor
- single molecule
- oxidative stress
- breast cancer cells
- crispr cas
- cell death
- induced apoptosis
- single cell
- binding protein
- mass spectrometry
- cell proliferation
- transcription factor
- amino acid
- high resolution
- atomic force microscopy
- stem cells
- reactive oxygen species
- cell therapy
- hiv testing
- fluorescent probe