CAVEOLIN IS PALMITOYLATED ON MULTIPLE CYSTEINE RESIDUES - PALMITOYLATION IS NOT NECESSARY FOR LOCALIZATION OF CAVEOLIN TO CAVEOLAE
CAVEOLIN IS PALMITOYLATED ON MULTIPLE CYSTEINE RESIDUES - PALMITOYLATION IS NOT NECESSARY FOR LOCALIZATION OF CAVEOLIN TO CAVEOLAE
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DOI：
10.1074/jbc.270.12.6838
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发表时间：
1995-03-24
影响因子：
4.8
通讯作者：
LUBLIN, DM
中科院分区：
文献类型：
--
作者：
DIETZEN, DJ;HASTINGS, WR;LUBLIN, DM
小窝是质膜的亚结构域，其浓缩胆固醇、鞘糖脂和糖基磷脂酰肌醇连接蛋白。最近已经证明，蛋白酪氨酸激酶的Src家族的特定成员需要棕榈酰化的NH 2-末端半胱氨酸残基定位在小窝。在这里，我们报告，小窝，一个完整的膜蛋白，形成的外套小窝的一部分，也通过连接半胱氨酸残基的棕榈酸。小窝蛋白仅含有三个半胱氨酸残基，它们都位于疏水性跨膜区的COOH末端侧。用小窝蛋白转染的细胞的免疫荧光染色表明，像NH 2末端，这COOH-末端区域位于质膜的细胞质侧。半胱氨酸取代突变体的研究表明，所有三个半胱氨酸都能够掺入棕榈酸，并且质膜Cys（133）残基是棕榈酰化的主要位点。同时突变的所有三个半胱氨酸残基的窖蛋白导致的能力，将棕榈酸酯的损失，但是，这并不影响本地化的蛋白质。因此，棕榈酰化的半胱氨酸残基在非跨膜Src家族蛋白酪氨酸激酶有不同的后果比跨膜蛋白小窝蛋白。
Caveolae are subdomains of the plasma membrane which concentrate cholesterol, glycosphingolipids, and glycosylphosphatidylinositol-linked proteins. It has recently been demonstrated that specific members of the Src family of protein tyrosine kinases require palmitoylation of NH2-terminal cysteine residues to localize in caveolae. Here we report that caveolin, an integral membrane protein which forms part of the coat of caveolae, also incorporates palmitate through linkage to cysteine residues. Caveolin contains only three cysteine residues which are all located on the COOH-terminal side of the hydrophobic transmembrane region. Immunofluorescent staining of cells transfected with caveolin indicated that, like the NH2 terminus, this COOH-terminal region is located on the cytoplasmic side of the plasma membrane. Studies of cysteine substitution mutants showed that all three cysteines are capable of incorporating palmitate and that the juxtamembrane Cys(133) residue is the predominant site of palmitoylation. Simultaneous mutation of all three cysteine residues in caveolin resulted in the loss of ability to incorporate palmitate; however, this did not affect localization of the protein. Thus, palmitoylation of cysteine residues in nonmembrane spanning Src family protein tyrosine kinases has different consequences than in the transmembrane protein caveolin.