Organellisia

Organellisia is a hypothetical class of intracellular compartments proposed in speculative biology to describe modular, dynamic reaction microcompartments within the cytoplasm. In this conceptual framework, organellisia function as semi-autonomous units that can assemble around specific enzymatic tasks and disassemble when their work is done, enabling flexible reconfiguration of cellular metabolism.

They are imagined as small vesicular or shell-like structures, on the scale of tens to a few hundred nanometers, enclosed by a lipid bilayer or a proteinaceous coat. They form by self-assembly from scaffold proteins, lipids, and targeted enzyme complexes, and may bud from existing membranes or emerge de novo in response to cellular signals. Their positioning within the cell can be directed by the cytoskeleton, allowing targeted delivery of substrates or exclusion of incompatible reactions. They are typically described as having selective permeability, concentrating substrates, and providing distinct local environments to modulate reaction kinetics.

Proposed functions include sequestration of reactive intermediates, enhancement of metabolic flux through proximity effects, and insulation of parallel pathways to reduce cross-talk. Some models also assign signaling roles to organellisia by concentrating signaling molecules within a defined space.

There is no established empirical evidence for organellisia in real cells; the concept appears mainly in speculative discussions, thought experiments, and science fiction as a way to explore modular organization of metabolism or the potential of synthetic biology to engineer new cellular compartments.

Etymology: the name combines organelle with the suffix -ia to denote a class or group.