The proteomic inventory reveals the chloroplast ribosome as nexus within a diverse protein network

ABSTRACT: In plant cells, chloroplast gene expression is predominantly controlled through regulation of translation. Fine-tuning of protein synthesis is vital for plant development, acclimation to environmental challenges and for the assembly of major protein complexes such as the photosynthesis machinery. However, little is known about the degree and nature of the regulatory network, mainly due to challenges associated with the specific isolation of chloroplast ribosomes under conditions that also retain weak or transient interactions. Here, we established a ribosome affinity purification method, which enabled us to map the global interaction network of chloroplast ribosomes. Endogenously tagging a protein of the large or small subunit revealed not only interactors of the holo complex, but also preferential interactors of the two subunits. This includes known canonical regulatory proteins as well as several new proteins belonging to the categories of protein and RNA regulation, photosystem biogenesis, redox control and plastidic metabolism. By further characterizing identified proteins, we provide the first evidence for the existence of a co-translational N-acetyltransferase process in chloroplasts. Our dataset establishes the chloroplast ribosome as nexus in a highly choreographed, spatially interconnected protein network and reveals its wide-ranging regulatory potential during gene expression.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Chlamydomonas Reinhardtii

TISSUE(S): Cell Suspension Culture

SUBMITTER: Robin Roth  

LAB HEAD: Zuzana Storchova

PROVIDER: PXD020377 | Pride | 2021-01-04

REPOSITORIES: Pride