Vesicles is a collective term for small structures or organelles enclosed by a lipid bilayer. Transport vesicles represent a major way of intracellular transport of proteins and lipids between different cellular compartments. Secretory vesicles are used for the release of substances to the exterior of the cell through exocytosis. Other vesicles, including endosomes and lysosomes, are used for uptake and degradation of cargo from outside the cell by endocytosis or phagocytosis, or from inside the cell by autophagocytosis. There are also vesicles, such as peroxisomes, that have specialized metabolic functions. Both the membrane components, potential coating proteins, and contents of vesicles varies, depending on the type of vesicle, but also cell type.
Vesicle stainings usually appear as small and bright dots in the cytoplasm. Although the staining pattern can indicate towards a specific type of vesicle, there is no certainty without co-staining with marker dyes or of marker proteins. Therefore, vesicle-like stainings are annotated as "vesicles" in the Cell Atlas, while the terms "endosomes", "lysosomes" and "peroxisomes" are only used if colocalization experiments have been carried out.
Read more about the proteome of vesicles.