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

J Blaine, K Okamura, H Giral… - … of Physiology-Cell …, 2009 - journals.physiology.org
J Blaine, K Okamura, H Giral, S Breusegem, Y Caldas, A Millard, N Barry, M Levi
American Journal of Physiology-Cell Physiology, 2009journals.physiology.org
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 …
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.
American Physiological Society