Leitzke Sinje, Seidel Jana, Ahrens Björn, Schreiber Rainer, Kunzelmann Karl, Sperrhacke Maria, Bhakdi Sucharit, Reiss Karina
Department of Dermatology, University of Kiel, 24105 Kiel, Germany.
Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
Membranes (Basel). 2022 Jan 20;12(2):123. doi: 10.3390/membranes12020123.
Ca-activated Cl channels (TMEM16, also known as anoctamins) perform important functions in cell physiology, including modulation of cell proliferation and cancer growth. Many members, including TMEM16F/ANO6, additionally act as Ca-activated phospholipid scramblases. We recently presented evidence that ANO6-dependent surface exposure of phosphatidylserine (PS) is pivotal for the disintegrin-like metalloproteases ADAM10 and ADAM17 to exert their sheddase function. Here, we compared the influence of seven ANO family members (ANO1, 4, 5, 6, 7, 9, and 10) on ADAM sheddase activity. Similar to ANO6, overexpression of ANO4 and ANO9 led to increased release of ADAM10 and ADAM17 substrates, such as betacellulin, TGFα, and amphiregulin (AREG), upon ionophore stimulation in HEK cells. Inhibitor experiments indicated that ANO4/ANO9-mediated enhancement of TGFα-cleavage broadened the spectrum of participating metalloproteinases. Annexin V-staining demonstrated increased externalisation of PS in ANO4/ANO9-overexpressing cells. Competition experiments with the soluble PS-headgroup phosphorylserine indicated that the ANO4/ANO9 effects were due to increased PS exposure. Overexpression of ANO4 or ANO9 in human cervical cancer cells (HeLa), enhanced constitutive shedding of the growth factor AREG and increased cell proliferation. We conclude that ANO4 and ANO9, by virtue of their scramblase activity, may play a role as important regulators of ADAM-dependent cellular functions.
钙激活氯离子通道（TMEM16，也称为anoctamins）在细胞生理学中发挥重要作用，包括调节细胞增殖和癌症生长。许多成员，包括TMEM16F/ANO6，还可作为钙激活磷脂翻转酶。我们最近提供的证据表明，依赖ANO6的磷脂酰丝氨酸（PS）表面暴露对于解整合素样金属蛋白酶ADAM10和ADAM17发挥其蛋白酶功能至关重要。在此，我们比较了七个ANO家族成员（ANO1、4、5、6、7、9和10）对ADAM蛋白酶活性的影响。与ANO6类似，在HEK细胞中经离子载体刺激后，ANO4和ANO9的过表达导致ADAM10和ADAM17底物（如β细胞素、TGFα和双调蛋白（AREG））的释放增加。抑制剂实验表明，ANO4/ANO9介导的TGFα切割增强拓宽了参与的金属蛋白酶谱。膜联蛋白V染色显示，在ANO4/ANO9过表达细胞中PS的外化增加。用可溶性PS头部基团磷酸丝氨酸进行的竞争实验表明，ANO4/ANO9的作用是由于PS暴露增加。在人宫颈癌细胞（HeLa）中过表达ANO4或ANO9可增强生长因子AREG的组成性切割并增加细胞增殖。我们得出结论，ANO4和ANO9凭借其翻转酶活性，可能作为ADAM依赖的细胞功能的重要调节因子发挥作用。
