Characterization of the physical interaction of Gli proteins with SUFU proteins
Characterization of the physical interaction of Gli proteins with SUFU proteins
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DOI：
10.1074/jbc.m209492200
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发表时间：
2003-02-14
影响因子：
4.8
通讯作者：
Toftgard, R
中科院分区：
文献类型：
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作者：
Dunaeva, M;Michelson, P;Toftgard, R
刺猬信号通路在多种生物的发育和癌症诱导中都有参与。刺猬信号转导级联的终点是Gli/Ci，锌指转录因子。融合抑制因子（SUFU）、Costal-2和蛋白激酶A等蛋白对Gli/Ci加工、活性和定位的调节至关重要。共免疫沉淀和Far Western试验，加上截断分析和诱变已被用于确定Gli蛋白与SUFU之间的相互作用区域。我们在Gli/Ci家族蛋白中发现了一个新的基序SYGH，这是与SUFU相互作用所必需的。突变研究表明，Gly（122）和His（123）对于SUFU的结合至关重要，这表明疏水性对于正确的结合构象至关重要。功能分析显示，该基序突变的GLI转录因子活性不再被SUFU的共表达所抑制。此外，我们发现SUFU中c端19个氨基酸的缺失（Delta465）足以消除与GLI1的相互作用。有趣的是，这种SUFU突变体定位于细胞核，很可能是因为它不能有效地隔离在细胞质中。综上所述，我们在Gli/Ci蛋白家族中发现了一个新的基序，该基序对于与SUFU的蛋白-蛋白相互作用以及SUFU对GLI1的功能抑制都是必不可少的。
The Hedgehog signaling pathway is involved in both development and cancer induction in a wide range of organisms. The end point of the Hedgehog signal-transduction cascade is the Gli/Ci, zinc-finger transcription factors. Proteins such as Fused, Suppressor of fused (SUFU), Costal-2, and protein kinase A are essential for regulation of Gli/Ci processing, activity, and localization. Coimmunoprecipitation and Far Western assays, coupled with truncation analysis and mutagenesis have been used to define the region of interaction between Gli proteins and SUFU. We identify a novel motif SYGH in Gli/Ci family proteins, which is required for the interaction with SUFU. Mutational studies revealed that Gly(122) and His(123) are crucial for binding to SUFU, suggesting the importance of hydrophobicity for the correct binding conformation. Functional analysis revealed that the activity of GLI transcription factors with mutations in this motif is no longer suppressed by coexpression of SUFU. Moreover, we have found that a C-terminal 19-amino acid deletion in SUFU (Delta465) is sufficient to abrogate interaction with GLI1. Interestingly, this SUFU mutant localizes in the nucleus, most probably because it is not efficiently sequestered in the cytoplasm. Taken together, we identified a novel motif in the Gli/Ci family of proteins that is essential both for protein-protein interaction with SUFU and for functional repression of GLI1 by SUFU.