The function of the kidneys is to maintain normal ionic concentrations in the blood. Normally the kidneys maintain the blood ionic composition within very tight range and imbalance produces very serious health consequences including death. The goal of this grant is to understand the ion channels that function in the kidney to transport chloride and maintain chloride homeostasis in the body. This application will focus on an exciting new family of chloride channels that was just discovered, the anoctamins (also called TMEM16). We have preliminary data that several anoctamins are expressed in kidney and are likely to play important roles in chloride secretion and/or absorption. This application will investigate the expression of anotamins in normal mouse and human kidney and in kidney from human and from mouse models of polycystic kidney disease. Expression will be determined using quantitative RT-PCR, western blot, and immunofluorescent confocal microscopy. The functional structure and organization of the anoctamin channel will be investigated using electrophysiological (whole-cell and single channel patch clamp recording) and biochemical analysis of cells expressing Ano1. The location of Ca2+ binding sites and mechanisms of regulation of Ano1 by voltage and Ca2+ will be explored to develop a quantitative model of how anoctamin channels are gated.
Kidneys function to filter approximately 200 liters of blood per day in order to remove toxic substances and to regulate the ionic composition of the body. These studies will elucidate the mechanisms of chloride transport by the kidney and will make inroads into identifying mechanisms that hopefully will be useful in treating various kinds of kidney disease including diabetic kidney disease, high blood pressure, autoimmune diseases, and genetic diseases such as polycystic kidney disease.
|Whitlock, Jarred M; Hartzell, H Criss (2016) A Pore Idea: the ion conduction pathway of TMEM16/ANO proteins is composed partly of lipid. Pflugers Arch 468:455-73|
|Ye, Zhen; Wu, Ming-Ming; Wang, Chun-Yu et al. (2015) Characterization of Cardiac Anoctamin1 CaÂ²âº-Activated Chloride Channels and Functional Role in Ischemia-Induced Arrhythmias. J Cell Physiol 230:337-46|
|Lee, Jesun; Jung, Jooyoung; Tak, Min Ho et al. (2015) Two helices in the third intracellular loop determine anoctamin 1 (TMEM16A) activation by calcium. Pflugers Arch 467:1677-87|
|Yu, Kuai; Whitlock, Jarred M; Lee, Kyleen et al. (2015) Identification of a lipid scrambling domain in ANO6/TMEM16F. Elife 4:e06901|
|Wu, Ming-Ming; Lou, Jie; Song, Bin-Lin et al. (2014) Hypoxia augments the calcium-activated chloride current carried by anoctamin-1 in cardiac vascular endothelial cells of neonatal mice. Br J Pharmacol 171:3680-92|
|Ruppersburg, Chelsey Chandler; Hartzell, H Criss (2014) The Ca2+-activated Cl- channel ANO1/TMEM16A regulates primary ciliogenesis. Mol Biol Cell 25:1793-807|
|Xiao, Qinghuan; Cui, Yuanyuan (2014) Acidic amino acids in the first intracellular loop contribute to voltage- and calcium- dependent gating of anoctamin1/TMEM16A. PLoS One 9:e99376|
|Yu, Kuai; Zhu, Jinqiu; Qu, Zhiqiang et al. (2014) Activation of the Ano1 (TMEM16A) chloride channel by calcium is not mediated by calmodulin. J Gen Physiol 143:253-67|
|Hartzell, H Criss; Ruppersburg, Chelsey Chandler (2013) Functional reconstitution of a chloride channel bares its soul. Proc Natl Acad Sci U S A 110:19185-6|
|Oh, Soo-Jin; Hwang, Seok Jin; Jung, Jonghoon et al. (2013) MONNA, a potent and selective blocker for transmembrane protein with unknown function 16/anoctamin-1. Mol Pharmacol 84:726-35|
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