Stimuli-driven coacervates are quite similar to modern stress granules in terms of how they assemble/disassemble. Stress granules are formed when cells are subjected to extremes of pH, temperature, ionic stress, etc. to protect cellular proteins and RNA from degradation and prevent the formation of misfolded proteins, which could lead to aberrant cellular function. When these environmental stresses are not present, the stress granules are disassembled. The assembly and disassembly of stress granules are controlled by the phosphorylation/dephosphorylation of translation-associated proteins in response to external stresses. eIF2a, a protein complex involved in translation initiation, is phosphorylated by eIF2α kinase. This prevents the initiation of translation and leads to the encapsulation of RBPs, ribosomal subunits, translation initiation factors and translationally arrested mRNAs into stress granules. A decrease in stress leads to the dephosphorylation of eIF2α, which leads to the disassembly of stress granules and the resumption of the initiation of translation. Similar to the assembly and disassembly mechanism of stress granules, some simple in vitro coacervates have been synthesized which can assemble and disassemble due to phosphorylation and dephosphorylation, respectively. A study showed that phosphorylation and dephosphorylation of serines in a peptide sequence that formed a particular type of coacervate led to the assembly and disassembly of the coacervate, respectively. Peptide/nucleotide coacervates which could be assembled by phosphorylating ADP to ATP and vice-versa were also synthesized. However, the fact remains that in vitro coacervates are much simpler in function and composition as compared to membraneless organelles, and these studies investigated only direct phosphorylation/dephosphorylation-they do not analyze whether these reactions take place as a result of changes in environmental stress factors. Nevertheless, the fact that simple in vitro coacervates can be regulated by enzymatic reactions that also regulate stress granule assembly/disassembly during stress hints towards the possibility that the assembly/disassembly of primitive coacervates could have been regulated by phosphorylation/dephosphorylation type reactions (possibly non-enzymatic as well). In particular, non-enzymatic phosphorylation has been shown to be thermodynamically feasible in prebiotic Earth conditions, while phosphorylation of molecules has been shown to occur abiotically in phase separated aqueous microdroplets. This suggests that phosphorylative control of primitive coacervate assembly/assembly could have been possible via primitive environmental fluctuations, which themselves could have allowed components encapsulated within coacervates to access cyclical changes in environmental conditions (i.e., stressors). Thus, assembly/disassembly could lead to chemical evolution even in membraneless compartments.