# ATP13A2 is involved in intracellular polyamine transport in lung epithelial cells

## TL;DR

ATP13A2 transports polyamines in lung cells, with its activity linked to cell growth and polyamine levels.

## Contribution

This study identifies ATP13A2 as a polyamine transporter in lung epithelial cells and shows its regulation during cell proliferation.

## Key findings

- ATP13A2 is endogenously expressed in mouse lungs and lung epithelial cells, with expression peaking during the logarithmic growth phase.
- ATP13A2 overexpression increases cellular polyamine levels, while knockdown decreases them.
- ATPase activity in ATP13A2-enriched microsomes is polyamine-dependent in lung cells.

## Abstract

Polyamines are present in all living cells and are implicated in various crucial cellular processes such as proliferation, apoptosis and autophagy. In contrast, excess amounts of polyamines can be toxic to cells. ATP13A2 was recently identified as a mammalian polyamine transporter in neuronal cells. In this study, we attempted to characterize the function of ATP13A2 in cultured human lung epithelial cells. The data demonstrated that ATP13A2 is endogenously expressed in mouse lungs, and in cultured lung epithelial cells, the expression level of ATP13A2 drastically changes over culture time and peaks in the logarithmic phase during the proliferation curve. ATPase activity in ATP13A2‐enriched microsomes from lung cells showed polyamine dependence, as previously reported for other cell types and species. Overexpression of ATP13A2 caused a moderate increase in total cellular polyamine content, whereas ATP13A2 knockdown resulted in a decrease in cellular polyamine levels. These findings provide novel information regarding the cellular function of ATP13A2 in lungs and contribute to our understanding of cellular polyamine transport systems.

Spermidine transport in lung epithelial cells involves the polyamine transporter ATP13A2. Cell proliferation is associated with the upregulation of ATP13A2.