Purpose: To compare the interaction of human organic anion transporter hOAT4 with PDZ proteins between kidney cells and placental cells.
Materials and methods: PDZ proteins PDZK1 and NHERF1 were transfected into kidney LLC-PK1 cells and placental BeWo cells expressing hOAT4 or hOAT4-Delta, which lacks the PDZ consensus binding site. The interaction of PDZK1 and NHERF1 with hOAT4 and hOAT4-Delta was investigated by measurement of [3H] estrone sulfate uptake, cell surface and total cell expression of hOAT4.
Results: PDZK1 and NHERF1 enhanced hOAT4 activity in LLC-PK1 cells by increasing the cell surface expression of the transporter. In contrasts, these two PDZ proteins had no effect on hOAT4 activity in BeWo cells.
Conclusion: The interaction of PDZ proteins with hOAT4 may be cell-specific. In placenta, a different set of interacting proteins from PDZK1 and NHERF1 may be required to modulate hOAT4 activity.