Inhibition of G-protein betagamma-subunit functions by phosducin-like protein.
Inhibition of G-protein betagamma-subunit functions by phosducin-like protein.
复制标题
类磷蛋白对 G 蛋白 β-亚基功能的抑制。
DOI：
10.1073/pnas.93.5.2100
复制
发表时间：
1996
影响因子：
11.1
通讯作者：
M. Lohse
中科院分区：
文献类型：
--
作者：
S. Schröder;M. Lohse
磷酸脱氢酶是一种胞浆蛋白，主要在视网膜和松果体中表达，它可以与鸟嘌呤核苷酸结合蛋白(G蛋白)的β亚基相互作用，从而调节跨膜信号转导。最近从大鼠脑中分离到一种编码类磷酸脱氢蛋白(PhLP)的基因[Miles，M.F.，Barhite，S.，Sanga，M.&Elliott，M.(1993)Proc.娜塔莉。阿卡德。SCI。美国90,10831-10835。本文报道了PhLP在大肠杆菌中的表达及纯化。重组纯化的PUP可抑制G蛋白β亚基的多重作用。首先，它抑制百日咳毒素对纯化的α(O)的β-氨基丁酸依赖的ADP-核糖化。第二，对纯化的G(O)的GTP酶活性有抑制作用。PhLP在后一种方法中的IC50值为89 nM，而光滑素在17 nM时产生半最大抑制。最后，PhLP拮抗纯化的β-淀粉样亚基对视紫红质磷酸化的增强作用。PhLP的N端与硫代蛋白的较长的N端没有相似之处，该区域被证明是光还原蛋白-β-亚基相互作用的关键区域。因此，PhLP似乎通过一种未知的相互作用模式与G-蛋白β亚基结合，可能代表了G-蛋白功能的内源性调节。
Phosducin is a cytosolic protein predominantly expressed in the retina and the pineal gland that can interact with the betagamma subunits of guanine nucleotide binding proteins (G proteins) and thereby may regulate transmembrane signaling. A cDNA encoding a phosducin-like protein (PhLP) has recently been isolated from rat brain [Miles, M. F., Barhite, S., Sganga, M. & Elliott, M. (1993) Proc. Natl. Acad. Sci. USA 90, 10831-10835. Here we report the expression of PhLP in Escherichia coli and its purification. Recombinant purified PUP inhibited multiple effects of G-protein betagamma subunits. First, it inhibited the betagamma-subunit-dependent ADP-ribosylation of purified alpha(o) by pertussis toxin. Second, it inhibited the GTPase activity of purified G(o). The IC50 value of PhLP in the latter assay was 89 nM, whereas phosducin caused half-maximal inhibition at 17 nM. And finally, PhLP antagonized the enhancement of rhodopsin phosphorylation by purified betagamma subunits. The N terminus of PhLP shows no similarity to the much longer N terminus of phosducin, the region shown to be critical for phosducin-betagamma-subunit interactions. Therefore, PhLP appears to bind to G-protein betagamma subunits by an as yet unknown mode of interaction and may represent an endogenous regulator of G-protein function.