Evidence that palmitoylation of carboxyl terminus cysteine residues of the human luteinizing hormone receptor regulates postendocytic processing
Evidence that palmitoylation of carboxyl terminus cysteine residues of the human luteinizing hormone receptor regulates postendocytic processing
复制标题
DOI：
10.1210/me.2004-0335
复制
发表时间：
2005-03-01
影响因子：
--
通讯作者：
Menon, KMJ
中科院分区：
文献类型：
--
作者：
Munshi, UM;Clouser, CL;Menon, KMJ
棕榈酰化是G蛋白偶联受体超家族成员中一种高度保守的翻译后修饰。本研究探讨了棕榈酰化在人LH受体（LHR）的内吞和胞内后转运中的作用。通过将[H-3]棕榈酸掺入野生型（WT）或突变型受体（其中潜在的棕榈酰化位点C643和C644突变为甘氨酸残基）来确定LHR的棕榈酰化。WT受体显示[H-3]棕榈酸掺入成熟的90 kDa形式的受体，而两个Cys残基的突变废除了这种掺入，表明Cys 643和C644是棕榈酰化的位点。通过测试WT和突变体受体进行内化、再循环和溶酶体降解的能力，检查棕榈酰化在内吞作用和胞吞后加工中的作用。与野生型受体相比，突变型受体表现出增加的内化和减少的再循环，这表明在Cys 643和644处保留棕榈酸残基促进LHR再循环。棕榈酰化对受体再循环的作用得到证实，证明了一个不同的突变体，D578 H LHR，这是缺乏棕榈酰化，也回收效率较低。此外，数据表明，棕榈酰化，而不是内化率，决定了回收效率。本研究表明，棕榈酰化的半胱氨酸残基643和644的人LHR是一个决定因素的回收。
Palmitoylation is a well-conserved posttranslational modification among members of the G protein-coupled receptor superfamily. The present study examined the role of palmitoylation in endocytosis and postendocytic trafficking of the human LH receptor (LHR). Palmitoylation of the LHR was determined by incorporation of [H-3] palmitic acid into wild-type (WT) or mutant receptor in which the potential palmitoylation sites, C643 and C644, were mutated to glycine residues. The WT receptor showed incorporation of [H-3] palmitic acid into the mature 90-kDa form of the receptor whereas mutation of the two Cys residues abrogated this incorporation, indicating that Cys 643 and C644 are the sites of palmitoylation. The role of palmitoylation on endocytosis and postendocytic processing was examined by testing the ability of the WT and mutant receptor to undergo internalization, recycling, and lysosomal degradation. Compared with the WT receptor, the mutant receptor showed increased internalization and decreased recycling, suggesting that retention of palmitic acid residues at Cys 643 and 644 promotes LHR recycling. The role of palmitoylation on receptor recycling was substantiated by demonstrating that a different mutant, D578H LHR, which is deficient in palmitoylation, also recycled less efficiently. Furthermore, the data show that palmitoylation, not the rate of internalization, determines the efficiency of recycling. The present study shows that palmitoylation of cysteine residues 643 and 644 of the human LHR is a determinant of recycling.