National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)
RF1NS125674
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM128798
米国
National Institutes of Health/Office of the Director
S10OD032467
米国
引用
ジャーナル: bioRxiv / 年: 2024 タイトル: Cytoplasmic ribosomes on mitochondria alter the local membrane environment for protein import. 著者: Ya-Ting Chang / Benjamin A Barad / Hamidreza Rahmani / Brian M Zid / Danielle A Grotjahn / 要旨: Most of the mitochondria proteome is nuclear-encoded, synthesized by cytoplasmic ribosomes, and targeted to mitochondria post-translationally. However, a subset of mitochondrial-targeted proteins is ...Most of the mitochondria proteome is nuclear-encoded, synthesized by cytoplasmic ribosomes, and targeted to mitochondria post-translationally. However, a subset of mitochondrial-targeted proteins is imported co-translationally, although the molecular mechanisms governing this process remain unclear. We employ cellular cryo-electron tomography to visualize interactions between cytoplasmic ribosomes and mitochondria in . We use surface morphometrics tools to identify a subset of ribosomes optimally oriented on mitochondrial membranes for protein import. This allows us to establish the first subtomogram average structure of a cytoplasmic ribosome on the surface of the mitochondria in the native cellular context, which showed three distinct connections with the outer mitochondrial membrane surrounding the peptide exit tunnel. Further, this analysis demonstrated that cytoplasmic ribosomes primed for mitochondrial protein import cluster on the outer mitochondrial membrane at sites of local constrictions of the outer and inner mitochondrial membrane. Overall, our study reveals the architecture and the spatial organization of cytoplasmic ribosomes at the mitochondrial surface, providing a native cellular context to define the mechanisms that mediate efficient mitochondrial co-translational protein import.