vacuolare

Vacuolation, or vacuolization, is the process by which vacuoles form and enlarge within the cytoplasm of a cell. Vacuoles are membrane-bound compartments derived mainly from the endomembrane system, including the endoplasmic reticulum and Golgi apparatus. The vacuolar membrane, called the tonoplast in many plant and fungal cells, contains transport proteins and proton pumps that regulate pH, ions, and osmotic balance.

In plant cells, a prominent central vacuole serves several functions. It stores water and ions, contributing to turgor pressure that maintains cell rigidity. It also sequesters pigments, wastes, and secondary metabolites, and participates in degradation and recycling processes. The vacuole can occupy most of the cell volume, with its contents dynamically adjusted by trafficking to and from the cytoplasm.

In animal and fungal cells, vacuoles tend to be smaller and more transient, participating in storage, trafficking, and digestion. Lysosome-like vacuoles contain hydrolytic enzymes that digest macromolecules, while endocytic vacuoles form from vesicles that internalize extracellular material. In some protists, contractile vacuoles regulate osmotic balance by expelling excess water.

Vacuolation also occurs during autophagy, when autophagic vacuoles form to sequester cytoplasmic components for degradation in lysosomes. Environmental stress, nutrient deprivation, or developmental cues can trigger changes in vacuole number, size, and activity, reflecting the organelle’s role in storage, homeostasis, and cellular remodeling.

See also: vacuole, tonoplast, vacuolization, autophagy.