Palmitoylation of RGS proteins

RGS 蛋白的棕榈酰化

基本信息

批准号：
6432135
负责人：
TERESA L Z JONES
金额：
--
依托单位：
NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/6432135
关键词：
Escherichia coli G protein biological signal transduction cell free system cysteine fatty acylation gene expression guanosinetriphosphatase activating protein hydropathy membrane proteins palmitates protein purification thioester

项目摘要

RGS proteins (Regulators of G protein Signaling) are a recently discovered family of proteins that can turn-off G protein signaling by accelerating GTP hydrolysis and antagonizing G protein effectors. Their location, specificity and regulation within the cell are poorly understood. Presumably, they must be at the membrane to interact with G proteins and effectors. We found that the membrane affinity of RGS proteins could be increased by palmitoylation, the reversible modification with palmitate. RGS-GAIP, RGS 3, 4, 5, 10 and 16 underwent palmitoylation whereas two similar proteins RGS8 and RGS9 did not, suggesting that palmitoylation may differentiate the location or membrane binding of this family of proteins. Palmitoylation is critical for the function of RGS16. Mutation of cysteine residues at residues 2 and 12 in RGS16 blocks its palmitoylation and impairs its ability to inhibit both Gi and Gq-linked signaling pathways. The absence of palmitoylation did not alter the in vitro GTPase activity of RGS16 suggesting palmitoylation localizes RGS proteins to G proteins signaling components in the membrane. We investigated whether palmitoylation could target RGS proteins to membrane microdomains characterized by their resistance to detergents and enrichment in sphingolipids and cholesterol. RGS-GAIP and RGS16, but not the nonpalmitoylated RGS16 mutant, were found in these microdomains, called rafts. We are studying whether other RGS proteins are also localized in rafts and the functional consequences of this localization.

RGS蛋白（G蛋白信号的调节剂）是最近发现的蛋白质家族，可以通过加速GTP水解和拮抗G蛋白效应子来关闭G蛋白信号传导。他们的位置，特异性和细胞内的调节知之甚少。据推测，它们必须在膜上与G蛋白和效应子相互作用。我们发现，RGS蛋白的膜亲和力可以通过棕榈酰化（用棕榈酸酯的可逆修饰）增加。 RGS-GAIP，RGS 3、4、5、10和16进行了棕榈酰化，而两个相似的蛋白质RGS8和RGS9则没有，这表明棕榈酰化可能会区分该蛋白质家族的位置或膜结合。棕榈酰化对于RGS16的功能至关重要。在RGS16中残基2和12的半胱氨酸残基的突变阻断了其棕榈酰化，并损害其抑制GI和GQ连接信号通路的能力。棕榈酰化的不存在并没有改变RGS16的体外GTPase活性，这表明棕榈酰化将RGS蛋白定位在膜上G蛋白信号成分中。我们研究了棕榈酰化是否可以靶向RGS蛋白到膜微区，其特征是它们对洗涤剂的耐药性和作为鞘脂脂和胆固醇的富集为特征。 RGS-GAIP和RGS16，但未在这些微区域（称为Rafts）中发现非贴酰胺的RGS16突变体。我们正在研究其他RGS蛋白是否也位于筏子和该定位的功能后果中。