Targeting of Vacuolar Membrane Localized Members of the TPK Channel Family
Targeting of Vacuolar Membrane Localized Members of the TPK Channel Family
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DOI：
10.1093/mp/ssn064
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发表时间：
2008-11-01
期刊：
影响因子：
27.5
通讯作者：
Hedrich, Rainer
中科院分区：
文献类型：
--
作者：
Dunkel, Marcel;Latz, Andreas;Hedrich, Rainer
拟南芥串联孔钾通道家族的四个成员（TPK 1、2、3和5）位于液泡膜中，而TPK 4是质膜K+通道。通过构建TPK 1和TPK 4之间的嵌合体，我们试图识别参与运输过程的通道结构域，并发现TPK 1细胞质C-末端结构域（CT）对于ER-以及高尔基体-分选步骤至关重要。定点诱变后，我们确定了TPK 1 ER-出口所需的二酸基序（IDLE）。然而，这种在C-末端的二酸基序在TPK家族的其他成员中是不保守的，并且TPK 3分选不依赖于其CT。此外，通道激活所必需的TPK 1的14-3-3结合位点不参与通道分选。
Four members of the tandem-pore potassium channel family of Arabidopsis thaliana (TPK1, 2, 3, and 5) reside in the vacuolar membrane, whereas TPK4 is a plasma membrane K+-channel. By constructing chimeras between TPK1 and TPK4, we attempted to identify channel domains involved in the trafficking process and found that the TPK1 cytoplasmic C-terminal domain (CT) is critical for the ER- as well as Golgi-sorting steps. Following site-directed mutagenesis, we identified a diacidic motif (IDLE) required for ER-export of TPK1. However, this diacidic motif in the C-terminus is not conserved among other members of the TPK family, and TPK3 sorting is independent of its CT. Moreover, the 14-3-3 binding site of TPK1, essential for channel activation, is not involved in channel sorting.