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PTH-induced internalization of apical membrane NaPi2a: role of actin and myosin VI

2009; American Physical Society; Volume: 297; Issue: 6 Linguagem: Inglês

10.1152/ajpcell.00260.2009

1522-1563

Judith Blaine, Kayo Okamura, Héctor Giral, Sophia Y. Breusegem, Yupanqui Caldas, Andrew C. Millard, Nicholas P. Barry, Moshe Levi,

Erythrocyte Function and Pathophysiology

Parathyroid hormone (PTH) plays a critical role in the regulation of renal phosphorous homeostasis by altering the levels of the sodium-phosphate cotransporter NaPi2a in the brush border membrane (BBM) of renal proximal tubular cells. While details of the molecular events of PTH-induced internalization of NaPi2a are emerging, the precise events governing NaPi2a removal from brush border microvilli in response to PTH remain to be fully determined. Here we use a novel application of total internal reflection fluorescence microscopy to examine how PTH induces movement of NaPi2a out of brush border microvilli in living cells in real time. We show that a dynamic actin cytoskeleton is required for NaPi2a removal from the BBM in response to PTH. In addition, we demonstrate that a myosin motor that has previously been shown to be coregulated with NaPi2a, myosin VI, is necessary for PTH-induced removal of NaPi2a from BBM microvilli.