in early growth phase, and the majority of the 10% fatty acids observed under nitrogen-replete conditions is derived from structural membrane phospholipids. Interestingly, we observed steady-state abundance of DAGK between nitrogen-replete and nitrogen-deplete conditions. DAGK catalyzes the conversion of DAG to PA via phosphorylation of DAG, and its activity has been shown to increase upon activation of the phosphoinositide (PI) pathway. It is, therefore, proposed to function as a termination cue in the formation of DAG [48]. Steady state abundance may be indicative of steady-state activation of the PI pathway, potentially pointing to a minimal baseline phospholipid production level, required for cell viability. We hypothesize that future analyses using intermediate harvest points will lead to a less pronounced differential between fatty acid and TAG biosynthetic components, with an increased abundance of fatty acid components and a decrease in abundance of TAG components prior to nitrogen exhaustion. Future analyses will therefore be focused upon intermediate accumulation, which will allow for abundance mapping throughout the lipid accumulation cycle and help clarify the rates of TAG component expression. Concurrently, quantitative analyses of PA, DAG, and TAG will lend further insight into the flux through the TAG pathway, as well as temporal regulation throughout the lipid accumulation cycle. Conclusions The prevalence of microalgal translational gene regulation necessitates higher-level omic analyses at the protein level in order to fully elucidate changes in gene expression under varying conditions. 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