DAPLE protein inhibits nucleotide exchange on G?s and G?q via the same motif that activates G?i
DAPLE protein inhibits nucleotide exchange on G?s and G?q via the same motif that activates G?i
复制标题
DOI：
10.1074/jbc.ra119.011648
复制
发表时间：
2020-02-21
影响因子：
4.8
通讯作者：
Garcia-Marcos, Mikel
中科院分区：
文献类型：
--
作者：
Marivin, Arthur;Maziarz, Marcin;Garcia-Marcos, Mikel
除了受G蛋白的调控外偶联受体，异源三聚体G蛋白的活性由许多细胞质蛋白调节。GIV/Girdin和DAPLE（具有高频率亮氨酸的Dvl相关蛋白）是一组细胞质调节剂中最具特征的成员，其含有GIV-1。结合和激活（GBA）基序，其失调是人类疾病的基础，包括癌症和出生缺陷。GBA主题？含有蛋白质最初报道，以调节G蛋白结合G？G（i/o）亚基（G？(i))与其他家族（如G（s）、G（q/11）或G（12/13））相比，并促进体外核苷酸交换。然而，一些证据表明，这并不总是如此，磷酸化的GBA基序的GIV促进其结合G？(s)并抑制核苷酸交换。DAPLE的G蛋白特异性以及它如何影响G蛋白上的核苷酸交换？(i)仍有待调查。在这里，我们表明，DAPLE的GBA图案，除了G？(i)，有效地结合G（s）和G（q/11）家族成员（G？(s)而G？(q)，分别），但不是G（12/13）家族（G？(12))不存在翻译后磷酸化。我们确定了Met-1669作为DAPLE的GBA基序中的残基，该基序与GIV中的基序不同，能够更好地与G？(s)而G？（q）。不同于观察到的G核苷酸交换加速？(i)，DAPLE抑制G？(s)而G？（q）。这些研究结果表明，GBA基序在他们的G-蛋白？调节作用，即它们可以结合G？不同类别的亚基，并根据G蛋白亚型刺激或抑制核苷酸交换。
Besides being regulated by G-protein?coupled receptors, the activity of heterotrimeric G proteins is modulated by many cytoplasmic proteins. GIV/Girdin and DAPLE (Dvl-associating protein with a high frequency of leucine) are the best-characterized members of a group of cytoplasmic regulators that contain a G?-binding and -activating (GBA) motif and whose dysregulation underlies human diseases, including cancer and birth defects. GBA motif?containing proteins were originally reported to modulate G proteins by binding G? subunits of the G(i/o) family (G?(i)) over other families (such as G(s), G(q/11), or G(12/13)), and promoting nucleotide exchange in vitro. However, some evidence suggests that this is not always the case, as phosphorylation of the GBA motif of GIV promotes its binding to G?(s) and inhibits nucleotide exchange. The G-protein specificity of DAPLE and how it might affect nucleotide exchange on G proteins besides G?(i) remain to be investigated. Here, we show that DAPLE's GBA motif, in addition to G?(i), binds efficiently to members of the G(s) and G(q/11) families (G?(s) and G?(q), respectively), but not of the G(12/13) family (G?(12)) in the absence of post-translational phosphorylation. We pinpointed Met-1669 as the residue in the GBA motif of DAPLE that diverges from that in GIV and enables better binding to G?(s) and G?(q). Unlike the nucleotide-exchange acceleration observed for G?(i), DAPLE inhibited nucleotide exchange on G?(s) and G?(q). These findings indicate that GBA motifs have versatility in their G-protein?modulating effect, i.e. they can bind to G? subunits of different classes and either stimulate or inhibit nucleotide exchange depending on the G-protein subtype.