Phosphorylation of the atypical kinesin Costal2 by the kinase Fused induces the partial disassembly of the Smoothened-Fused-Costal2-Cubitus interruptus complex in Hedgehog signalling
Phosphorylation of the atypical kinesin Costal2 by the kinase Fused induces the partial disassembly of the Smoothened-Fused-Costal2-Cubitus interruptus complex in Hedgehog signalling
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DOI：
10.1242/dev.011577
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发表时间：
2007-10
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影响因子：
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通讯作者：
L. Ruel;Armel Gallet;S. Raisin;Arnaud Truchi;L. Staccini-Lavenant;A. Cervantes;P. Thérond
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文献类型：
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作者：
L. Ruel;Armel Gallet;S. Raisin;Arnaud Truchi;L. Staccini-Lavenant;A. Cervantes;P. Thérond
Hedgehog（Hh）家族的分泌蛋白参与发育和肿瘤发生过程。虽然这一重要途径的许多成员是已知的，但Hh信号转导的机制仍然知之甚少。在这项研究中，我们分析了Hh对驱动蛋白样蛋白Costal 2（Cos 2）的调控。我们表明，在Cos 2，丝氨酸572（Ser 572），一个残基是必要的Hh信号的正常转导从跨膜蛋白Smoothened（Smo）的转录介质肘中断（Ci）。该残基位于丝氨酸/苏氨酸激酶融合（Fu）结合结构域中，并由于Fu活化而被磷酸化。虽然Ser 572不与已知的Smo-或Ci-结合结构域重叠，但模拟组成性磷酸化的Cos 2变体的表达和磷酸化Ser 572的特异性抗体的使用显示磷酸化Cos 2与Smo和Ci的缔合在体外和体内均减少。此外，与Ala或Asp取代的Ser 572的Cos 2蛋白质受损，在他们的规管Ci活动。我们建议，激活Smo后，Fu激酶诱导Cos 2的构象变化，允许Smo-Fu-Cos 2-Ci复合物的解体和随后的Hh靶基因的激活。这项研究为介导Hh信号传导的蛋白质复合物的机制调节提供了新的见解，并为直接监测所有活化细胞中Hh受体活性提供了独特的抗体工具。
The Hedgehog (Hh) family of secreted proteins is involved both in developmental and tumorigenic processes. Although many members of this important pathway are known, the mechanism of Hh signal transduction is still poorly understood. In this study, we analyse the regulation of the kinesin-like protein Costal2 (Cos2) by Hh. We show that a residue on Cos2, serine 572 (Ser572), is necessary for normal transduction of the Hh signal from the transmembrane protein Smoothened (Smo) to the transcriptional mediator Cubitus interruptus (Ci). This residue is located in the serine/threonine kinase Fused (Fu)-binding domain and is phosphorylated as a consequence of Fu activation. Although Ser572 does not overlap with known Smo- or Ci-binding domains, the expression of a Cos2 variant mimicking constitutive phosphorylation and the use of a specific antibody to phosphorylated Ser572 showed a reduction in the association of phosphorylated Cos2 with Smo and Ci, both in vitro and in vivo. Moreover, Cos2 proteins with an Ala or Asp substitution of Ser572 were impaired in their regulation of Ci activity. We propose that, after activation of Smo, the Fu kinase induces a conformational change in Cos2 that allows the disassembly of the Smo-Fu-Cos2-Ci complex and consequent activation of Hh target genes. This study provides new insight into the mechanistic regulation of the protein complex that mediates Hh signalling and a unique antibody tool for directly monitoring Hh receptor activity in all activated cells.