It was shown that the big isoform localizes to vesicles with a higher motility in comparison to vacuoles, the small isoform was found to localize to. This indicates that   vesicles have a function in cellular transport, while vacuoles might store or digest proteins that are not required immediately. Since the speed of vesicles has a high variation and vesicles often pause between two or more movements, they might be loaded or components are taken off at different sites in the cell.

Vesicles containing the big form are no early endosomes and no lysosomes. Since they interact with both organelles, they might be either clathrin-coated vesicles that are transported from the plasma membrane to early endosomes or they are recycling endosomes and transport membrane targeted proteins to the plasma membrane.

The small isoform localizes to vacuoles that have a low motility. This indicates that they are not involved in cellular transport, but might have a function in storage or degradation of proteins that are not required in cell metabolism. Since it was shown that they do not have a pH similar to lysosomes, they do not contain acid hydrolases and are probably not involved in protein degradation. In contrast, they were shown to interact with lysosomes. Therefore, they might have a storing function in the cell and transfer proteins for degradation to lysosomes. Since vacuoles were mainly observed close to the nucleus, they are probably not involved in exocytosis. An interaction with other components of the secretory membrane system is probable, since the fusion of smaller vesicles might be the main mechanism of how vacuoles arise. This is supported, since the fusion of vacuoles and vesicles was observed and 5 ± 5 small vesicles were found in many cells. They might either be a vacuole precursor or a carrier for vacuole filling. However, auto-phagocytosis cannot be excluded as a mechanism of vacuole formation, but it was never observed in more than 1 h total observation of cells overexpressing the small isoform.