Anabaena Cyanoglobule Proteomics

Cyanoglobules (CGs) are thylakoid-associated lipid droplets in cyanobacteria that share compositional and functional features with plastoglobules (PGs) of plant chloroplasts. However, their roles in stress physiology remain poorly defined, particularly in filamentous cyanobacteria. Here, we characterize the CG proteome in a non-nitrogen-fixing (ΔN) strain of Anabaena sp. PCC 7120 under nitrogen deprivation, providing an unbiased framework to examine CG responses without the confounding influence of heterocyst differentiation or diazotrophy. Proteomic analysis revealed a conserved CG proteome enriched in plastoglobule homologs, redox regulators (NDC1, GRXC2), and isoprenoid metabolism enzymes (NDX1), supporting roles in pigment turnover and stress adaptation.