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Monitoring Kinase and Phosphatase Activities Through the Cell Cycle by Ratiometric FRET
Published on: January 27, 2012
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Kinase KEY1 controls pyrenoid condensate size throughout the cell cycle by disrupting phase separation interactions
Shan He1,2,3, Linnea M Lemma2,4, Alejandro Martinez-Calvo5,6,7
1Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
Nature Cell Biology
|March 18, 2026
Summary
A newly identified kinase, KEY1, controls the size and number of pyrenoid biomolecular condensates in algae. This kinase is crucial for pyrenoid dissolution during cell division and overall algal growth.
Area of Science:
- Cell Biology
- Biophysics
- Biochemistry
Background:
- Biomolecular condensates are essential for organizing cellular functions.
- The regulation of condensate dynamics, including size and number, remains poorly understood.
- The pyrenoid, a key algal condensate for CO2 fixation, undergoes dynamic changes during the cell cycle.
Purpose of the Study:
- To identify regulators of pyrenoid condensate size, number, and dissolution.
- To understand the role of these regulators in algal cell division and growth.
- To elucidate the molecular mechanisms governing pyrenoid dynamics.
Main Methods:
- Genetic analysis in Chlamydomonas reinhardtii to identify key regulators.
- Biophysical modeling to understand condensate dynamics.
- Biochemical assays to investigate protein interactions and phosphorylation.
Main Results:
- The kinase KEY1 was identified as a regulator of pyrenoid condensate size and number.
- key1 mutants exhibit multiple, smaller condensates that fail to dissolve during cell division.
- KEY1 promotes pyrenoid dissolution by phosphorylating EPYC1, disrupting Rubisco-EPYC1 interactions.
Conclusions:
- KEY1 is essential for normal pyrenoid function, growth, and cell cycle-dependent condensate dynamics.
- KEY1-mediated phosphorylation provides a mechanism for regulating condensate dissolution.
- These findings offer insights into the broader principles of biomolecular condensate regulation.
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