Abstract
The (C)F1 sector from H(+)-ATP synthases comprises five subunits: alpha, beta, gamma, delta and epsilon, assembled in a 3:3:1:1:1 stoichiometry. Here, we describe the molecular mechanism ensuring this unique stoichiometry, required for the functional assembly of the chloroplast enzyme. It relies on a translational feedback loop operating in two steps along the assembly pathway of CF1. In Chlamydomonas, production of the nucleus-encoded subunit gamma is required for sustained translation of the chloroplast-encoded subunit beta, which in turn stimulates the expression of the chloroplast-encoded subunit alpha. Translational downregulation of subunits beta or alpha, when not assembled, is born by the 5'UTRs of their own mRNAs, pointing to a regulation of translation initiation. We show that subunit gamma, by assembling with alpha(3)beta(3) hexamers, releases a negative feedback exerted by alpha/beta assembly intermediates on translation of subunit beta. Moreover, translation of subunit alpha is transactivated by subunit beta, an observation unprecedented in the biogenesis of organelle proteins.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
