Question

What does the title phrase ‘overcrowded milieu’ mean in the context of intrinsically disordered proteins, proteinaceous membrane-less organelles, and everything else constituting the cytoplasm? How do you think IDPs and PMLOs fit into the overall cytoplasmic content and at what ratio?

Answer 1

Eukaryotic cells contain numerous proteinaceous membrane-less organelles (PMLOs), which are condensed liquid droplets formed as a result of the reversible and highly controlled liquid-liquid phase transitions..PMLOs are invariantly enriched in intrinsically disordered proteins.The interior of these cellular bodies represents an overcrowded milieu, since their protein concentrations are noticeably higher than those of the crowded cytoplasm and nucleoplasm

IDPS domains preferentially localize to the cytoplasmic side especially of multi-pass transmembrane proteins, suggesting that disorder prediction could increase the confidence of topology prediction algorithms.Ratio is 2610:4316(54-65%)

Proteinaceous membrane-less organelles (PMLOs), also known as non-membranous cytoplasmic/nucleoplasmic granules, or cellular/nuclear micro-domains, or intracellular/ intranuclear bodies, that are commonly found in the nucleus and cytoplasm of various cells. The dimensions of PMLOs are cell size–dependent, and they contain proteins and RNA (and/or DNA). Since PMLOs are not covered by the membranes, their components are involved in direct contact and exchange with the nucleoplasm or cytoplasm.These liquid-droplet phases of the nucleoplasm/cytoplasm possess relatively low intrinsic density and viscosity that are comparable to those of the cytoplasm or nucleoplasm.Ratio is 25.50%