Obrdlik P, Neuhaus G, Merkle T
Institut für Biologie II, Zellbiologie, Universität Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany.
FEBS Lett. 2000 Jul 7;476(3):208-12. doi: 10.1016/s0014-5793(00)01706-3.
Gbeta subunits from animals are anchored to membranes via Ggamma subunits. No Ggamma has been identified in plants to date. Using differential centrifugation of Arabidopsis and broccoli extracts, Gbeta was highly enriched in the microsomal pellet. Treatment of microsomes with detergents and salts indicates that plant Gbeta is located at the membrane surface and attached to membranes by hydrophobic interactions. Analysis of transgenic plants expressing Gbeta-GFP fusion proteins showed that mutations in the heptad repeat domain of Gbeta severely diminished their membrane association. We propose that plant Gbeta is anchored to membranes by an unknown protein similar to animal Gbeta by Ggamma, via coiled-coil formation.
动物的Gβ亚基通过Gγ亚基锚定在膜上。迄今为止，尚未在植物中鉴定出Gγ亚基。通过对拟南芥和西兰花提取物进行差速离心，Gβ在微粒体沉淀中高度富集。用去污剂和盐处理微粒体表明，植物Gβ位于膜表面，并通过疏水相互作用与膜相连。对表达Gβ-GFP融合蛋白的转基因植物的分析表明，Gβ的七肽重复结构域中的突变严重削弱了它们与膜的结合。我们提出，植物Gβ通过类似于动物Gβ与Gγ亚基的未知蛋白质，通过形成卷曲螺旋结构锚定在膜上。
