F-box control of Multiple Organellar RNA Editing Factor 2 coordinates seed germination and plastid signaling

However, how plastid regulatory factors are dynamically controlled to modulate these signals remains largely unknown. Here we identify a proteostasis mechanism that regulates plastid retrograde signaling through the ubiquitin–26S proteasome system.

We show that the nuclear-encoded plastid RNA-editing factor MULTIPLE ORGANELLAR RNA EDITING FACTOR 2 (MORF2) is targeted for degradation by a Skp1–Cullin1–F-box (SCF) ubiquitin ligase assembled with the MORF2-INTERACTING F-BOX (MIF) protein. MIF physically associates with MORF2 and promotes its ubiquitylation and proteasome-dependent turnover. Genetic and physiological analyses reveal that this pathway balances early plant development.