Chloroplast ATP synthase biogenesis requires peripheral stalk subunits AtpF and ATPG and stabilization of atpE mRNA by OPR protein MDE1.

Chloroplast ATP synthase contains subunits of plastid and nuclear genetic origin. To investigate the coordinated biogenesis of this complex, we isolated novel ATP synthase mutants in the green alga Chlamydomonas reinhardtii by screening for high light sensitivity. We report here the characterization of mutants affecting the two peripheral stalk subunits b and b', encoded respectively by the atpF and ATPG genes, and of three independent mutants which identify the nuclear factor MDE1, required to stabilize the chloroplast-encoded atpE mRNA.

Converting antimicrobial into targeting peptides reveals key features governing protein import into mitochondria and chloroplasts.

We asked what peptide features govern targeting to the mitochondria versus the chloroplast, using antimicrobial peptides as a starting point. This approach was inspired by the endosymbiotic hypothesis that organelle-targeting peptides derive from antimicrobial amphipathic peptides delivered by the host cell, to which organelle progenitors became resistant. To explore the molecular changes required to convert antimicrobial into targeting peptides, we expressed a set of 13 antimicrobial peptides in Chlamydomonas reinhardtii.

Fast and global reorganization of the chloroplast protein biogenesis network during heat acclimation.

Photosynthesis is a central determinant of plant biomass production, but its homeostasis is increasingly challenged by heat. Little is known about the sensitive regulatory principles involved in heat acclimation that underly the biogenesis and repair of chloroplast-encoded core subunits of photosynthetic complexes. Employing time-resolved ribosome and transcript profiling together with selective ribosome proteomics, we systematically deciphered these processes in chloroplasts of Chlamydomonas reinhardtii.

Complexome profiling on the Chlamydomonas lpa2 mutant reveals insights into PSII biogenesis and new PSII associated proteins.

While the composition and function of the major thylakoid membrane complexes are well understood, comparatively little is known about their biogenesis. The goal of this work was to shed more light on the role of auxiliary factors in the biogenesis of photosystem II (PSII). Here we have identified the homolog of LOW PSII ACCUMULATION 2 (LPA2) in Chlamydomonas.