Diel Variations of Extracellular Microcystin Influence the Subcellular Dynamics of RubisCO in Microcystis aeruginosa PCC 7806

The ubiquitous freshwater cyanobacterium Microcystis is remarkably successful, showing a high tolerance against fluctuations in environmental conditions. It frequently forms dense blooms which can accumulate significant amounts of the hepatotoxin microcystin, plays an extracellular role as infochemical but also acts intracellularly by interacting with proteins carbon metabolism, notably CO2 fixing enzyme RubisCO. Here we demonstrate direct link between external microcystin and its intracellular targets. Monitoring liquid cultures diel experiment revealed content that correlate increase binding to proteins. Concomitantly, reversible relocation RubisCO from cytoplasm cell’s periphery was observed. These variations localization were especially pronounced grown at higher cell densities. We replicated these effects adding externally under continuous light. Thus, propose may be part fast response conditions light low contribute metabolic flexibility success field.