Location of the photosynthetic carbon metabolism in microcompartments and separated phases in microalgal cells

Unicellular photosynthetic cells are composed of an ensemble of partitions, also named microcompartments, that contribute to the regulation of carbon acquisition, assimilation and storage. This perspective Review proposes to consider the distinct physico-chemical properties of each microcompartments when considering the metabolic regulation. Reversibly, the activation of specific metabolic pathway modulates the physico-chemical properties of specific microcompartments. Carbon acquisition, assimilation and storage in eukaryotic microalgae and cyanobacteria occur in multiple compartments that have been characterised by the location of the enzymes involved in these functions. These compartments can be delimited by bilayer membranes, such as the chloroplast, the lumen, the peroxisome, the mitochondria; or monolayer membranes, such as lipid droplets or plastoglobules. They can also originate from liquid-liquid phase separation such as the pyrenoid. Multiple exchanges exist between the intracellular microcompartments and these are reviewed for the CO2 concentration mechanism, the Calvin-Benson-Bassham cycle, the lipid metabolism and the cellular energetic balance. Progress in microscopy and spectroscopic methods opens new perspectives to characterise the molecular consequences of the location of the proteins involved, including intrinsically disordered proteins.
Source: FEBS Letters - Category: Biochemistry Authors: Tags: Perspective Source Type: research