Towards modeling molecular cooperativity on the cellular scale

Formulated originally to describe the subtle blend of kinetics and thermodynamics that drives protein folding and ligand binding, the molecular cooperativity concept extrapolates readily to the cellular scale. Here it constitutes a thermally driven mode of cytological organization which can be provisionally explored within the equation of state (EOS) framework of classical statistical mechanics. We give a unified EOS account of the 'proto-cooperative' phenomena of phase separation and gelation in cytoplasm, emphasizing osmoregulatory control mechanism. In an extension to this framework, we show that a significant thermodynamic partitioning of ribosomes could occur spontaneously in conjunction with phase separation. This would be tantamount to a translation-transcription decoupling, with relevance to cellular evolution.