Palmitoylation of ERBIN is required for its plasma membrane localization
Palmitoylation of ERBIN is required for its plasma membrane localization
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DOI：
10.1111/j.1365-2443.2008.01198.x
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发表时间：
2008-07-01
期刊：
影响因子：
2.1
通讯作者：
Inagaki, Masaki
中科院分区：
文献类型：
--
作者：
Izawa, Ichiro;Nishizawa, Miwako;Inagaki, Masaki
富含亮氨酸重复序列（LRR）和PSD-95/Dlg/ZO-1（PDZ）家族蛋白，包括Scribble、LET-413、ERBIN、Densin-180和Lano，参与细胞极性的调节：据报道，PDZ蛋白的LRR结构域介导其基底外侧膜定位，并且对于其功能是必需的。为了进一步阐明ER-BIN的质膜定位机制，我们将ERBIN的各种突变体导入培养的细胞中，观察ERBIN的细胞内定位。当在氨基（N）末端区域缺少氨基酸残基1-32的LRR结构域突变体在细胞中过表达时，突变体不定位于质膜，而是定位于细胞质。我们发现ERBIN N-末端区域的半胱氨酸14和16在体内被棕榈酰化。半胱氨酸14和/或半胱氨酸16被改变为丝氨酸的过表达突变体不定位于质膜，表明ERBIN的棕榈酰化对其质膜定位是必需的。ERBIN的1-196个氨基酸的过度表达片段，缺乏LRR的后半部分，被棕榈酰化，但不定位于质膜。这些结果表明，棕榈酰化和LRR是必需的质膜定位ERBIN。
LAP (leucine-rich repeats (LRR) and PSD-95/Dlg/ZO-1 (PDZ)) family proteins, including Scribble, LET-413, ERBIN, Densin-180 and Lano, are involved in the regulation of cell polarity: The LRR domains of LAP proteins were reported to mediate their basolateral membrane localization and to be essential for their function. To further dissect the mechanism of the plasma membrane localization of ER-BIN, we introduced various mutants of ERBIN into cultured cells and observed the intracellular localization. When an LRR domain mutant lacking amino acid residues 1-32 at the amino (N) terminal region was over-expressed in cells, the mutant did not localize at the plasma membrane, but localized in the cytoplasm. We found that cysteines 14 and 16 at the N-terminal region of ERBIN are in vivo palmitoylated. Over-expressed mutants in which cysteine 14 and/or cysteine 16 were changed to serines did not localize at the plasma membrane, indicating that the palmitoylation of ERBIN is necessary for its plasma membrane localization. The over-expressed 1-196 amino acids fragment of ERBIN, which lacked the latter half of LRR, was palmitoylated but did not localize at the plasma membrane. These results suggest that both palmitoylation and LRR are required for the plasma membrane localization of ERBIN.