Scientists discovered a single master protein that coordinates when a plant's energy centers should grow versus when they should split.
March 31, 2026
Original Paper
Septin-mediated coupling of protein import and division during chloroplast evolution
bioRxiv · 10.64898/2026.03.28.715002
The Takeaway
For decades, it was assumed that an organelle's protein supply and its division into new units were separate processes. This study identifies a 'missing link' protein that physically connects these two systems, ensuring the chloroplast is fully stocked before it attempts to divide.
From the abstract
Chloroplast biogenesis depends on both protein import and organelle division, yet how their coordination emerged during evolution remains unclear. Here, we show that the single septin SEP1 links these pathways in the green alga Chlamydomonas reinhardtii. SEP1 forms a filamentous network on the chloroplast envelope during interphase and reorganizes into a ring at the chloroplast division site during cytokinesis. Loss of SEP1 selectively impairs import of chloroplast-division proteins and causes m