Parnell S C, Magenheimer B S, Maser R L, Rankin C A, Smine A, Okamoto T, Calvet J P
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, 66160, USA.
Biochem Biophys Res Commun. 1998 Oct 20;251(2):625-31. doi: 10.1006/bbrc.1998.9514.
Analysis of the C-terminal cytosolic domain of human and mouse polycystin-1 has identified a number of conserved protein motifs, including a 20-amino-acid heterotrimeric G-protein activation sequence. A peptide specific for this sequence was synthesized and shown to activate purified bovine brain heterotrimeric Gi/Go in vitro. To test whether the C-terminal cytosolic domain of polycystin-1 stably binds G-proteins, GST-fusion constructs were used in pull-down and co-immunoprecipitation assays with purified bovine brain Gi/Go and rat brain lysates. This identified a 74-amino-acid minimal binding domain that includes the G-protein activation sequence. This region of polycystin-1, including the G-protein activation peptide and flanking amino acid sequences, is highly conserved in mouse, human, and puffer fish, lending further support to the functional importance of the minimal binding domain. These results suggest that polycystin-1 may function as a heterotrimeric G-protein coupled receptor.
对人和小鼠多囊蛋白-1的C端胞质结构域进行分析，已鉴定出一些保守的蛋白质基序，包括一个20个氨基酸的异源三聚体G蛋白激活序列。合成了针对该序列的肽，并证明其在体外可激活纯化的牛脑异源三聚体Gi/Go。为了测试多囊蛋白-1的C端胞质结构域是否能稳定结合G蛋白，在与纯化的牛脑Gi/Go和大鼠脑裂解物的下拉和共免疫沉淀试验中使用了GST融合构建体。这确定了一个包含G蛋白激活序列的74个氨基酸的最小结合结构域。多囊蛋白-1的这一区域，包括G蛋白激活肽和侧翼氨基酸序列，在小鼠、人类和河豚中高度保守，进一步支持了最小结合结构域的功能重要性。这些结果表明，多囊蛋白-1可能作为一种异源三聚体G蛋白偶联受体发挥作用。
