H2020Индивидуална стипендия2018–2020

ItohRibo · Structural study on mitochondrial ribosome assembly in human cells

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2018-06-21 → 2020-06-20
Финансиране от ЕС: 173 857 €
Участници: 1
Схема: MSCA-IF-EF-ST

Линиите свързват координатора с партньорите.

Накратко на български

Митохондриалните рибозоми в човешките клетки се сглобяват чрез сложен процес, при който протеини от ядрото се съединяват с РНК от митохондриите. Разбирането на тези стъпки помага да се разбере как функционира синтезът на протеини в митохондриите.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Structural study on mitochondrial ribosome assembly in human cells

The protein synthesis machinery, the ribosome, is not constructed of freely diffusing macromolecules; rather, its formation is an intricate and well-defined hierarchical process involving hundreds of proteins and a few RNA molecules working in cooperation and under tight regulation. In mitochondria, this fundamental process has an additional level of complexity, as it requires cooperative effort involving the precise regulation of two genomes. Although mitochondrial rRNAs are encoded in the mitochondrial genome, all 82 proteins of mitochondrial ribosome (mitoribosome) and numerous assembly factors are encoded in the nuclear genome and are therefore imported from cytosol. The high complexity of mitoribosomal assembly, and the unique association of a tRNA as a structural component of mitoribosome imply the involvement of as-yet-unknown mitochondria-specific auxiliary factors. Because many of the features of this system are unique to mitochondria, which have traditionally been difficult to investigate, little is known about the process of mitoribosome assembly. I expected to reveal mechanistic insights into how mitoribosomal proteins are assembled in a cascade while nascent mitochondrial rRNA molecules are processed and folded. Since high resolution cryo-EM allows now a unique ability to investigate heterogeneous ribosomal populations and built de novo models, the proposed work will not only reveal maturation states, but also new factors in the mitoribosome assembly process. Overall goal was to describe the full molecular sequence of the maturation steps along the ribosomal assembly pathway time line in human mitochondria and to put that sequence in the mirochondrial-cellular context. The objectives aimed to act on the fundamental question of the mitochondrial protein synthesis machinery assembly and uncover first insights into how unprecedented structural occurrences, unique to the ribosomes from human mitochondria, are formed. During the period, in total of 6 assembly intermediate states from human mitochondria were identified by extensive 3D classifications of cryo-EM data and the model fitting is going on. In additon, two pre-initiation complexes of translation were also identified and published.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

Human mitoribosome represents a distinct class of ribosomes that has specialized in synthesizing exclusively 13 hydrophobic membrane proteins, forming the catalytic core of the respiratory chain. The mature mitoribosome is composed of 82 nuclear encoded proteins and three mt-rRNAs. It is postulated that mitoribosomes are formed in an intricate and well-defined hierarchical process, involving hundreds of proteins and RNA molecules working in cooperation and under tight regulation. However, a structural insight into this process is completely lacking and most of the trans-factors remain unknown. I propose to fill this gap by harnessing CRISPR/Cas9 for genome editing in combination with the state of the art methods in single particle cryo-electron microscopy (cryo-EM). By combining these techniques with biochemical characterization, I will reveal mechanistic insights into how mitoribosomal proteins are assembled in a cascade while nascent mitochondrial rRNA molecules are processed and folded. Since high resolution cryo-EM allows now a unique ability to investigate heterogeneous ribosomal populations and built de novo models, the proposed work will not only reveal the maturation states, but also currently unknown factors implicated in the process. On the other hand, the mitochondrion is compartmentalized into sub-organelle sections such as nucleoids, RNA granules, and membrane-related milieus, and they co-localize with various stages of the mitoribosome assembly. I will also use cryo-electron tomography (cryo-ET) to expand the scope beyond the mitoribosomal complexes and reveal the dynamics of the maturation process and transport mechanism of the assembly intermediates between the sub-organelle compartments. Our approach relies on the most recently developed methodologies and proven strength of the lab complemented by specialized expertise of collaborators, aiming to characterize the transient and low abundant complexes in human mitochondria.

Оригинален текст от CORDIS (на английски).

Участници

STOCKHOLMS UNIVERSITET · StockholmКоординаторШвеция