B56β, a regulatory subunit of protein phosphatase 2A, interacts with CALEB/NGC-mediated dendritic branching
B56β, a regulatory subunit of protein phosphatase 2A, interacts with CALEB/NGC-mediated dendritic branching
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DOI：
10.1096/fj.07-096115
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发表时间：
2008-07-01
期刊：
影响因子：
4.8
通讯作者：
Schumacher, Stefan
中科院分区：
文献类型：
--
作者：
Brandt, Nicola;Franke, Kristin;Schumacher, Stefan
由于树突是突触输入的主要场所，树突乔木的发育在神经元回路的形成中至关重要。被称为棘的形态上专门化的树枝状突起代表兴奋性神经传递的主要突触后隔室。最近，我们证明了鸡酸性亮氨酸丰富的表皮生长因子（EGF）样结构域含有脑蛋白/神经聚糖C（CALEB/ NGC），EGF家族的神经成员，介导树突树和脊柱的复杂性，但在各自的过程中的信号通路不同。为了更详细地表征这些信号转导途径，我们进行了酵母双杂交筛选，以鉴定与CALEB/NGC相互作用的蛋白质。我们的研究结果表明，B56 β，蛋白磷酸酶2A的调节亚基，与CALEB/NGC相互作用，并抑制CALEB/NGC介导的树突状分支，但不棘的形成。B56 β与CALEB/NGC的结合通过几种生物化学和免疫细胞化学测定来证实。使用亲和层析和质谱，我们证明了整个蛋白磷酸酶2A三聚体，包括结构和催化亚基，通过B56 β结合CALEB/NGC。我们发现CALEB/NGC诱导树突中Akt的磷酸化。B56 β先前被描述为干扰Akt信号传导，其抑制由CALEB/NGC诱导的Akt磷酸化和Akt依赖性树突状分支，但不抑制Akt非依赖性棘形成。我们的研究结果有助于更好地理解信号特异性，导致神经元的过程分化的顺序发展的事件。
The development of dendritic arbors is critical in neuronal circuit formation, as dendrites are the primary sites of synaptic input. Morphologically specialized dendritic protrusions called spines represent the main postsynaptic compartment for excitatory neuro-transmission. Recently, we demonstrated that chicken acidic leucine-rich epidermal growth factor (EGF) -like domain-containing brain protein/neuroglycanC(CALEB/ NGC), a neural member of the EGF family, mediates dendritic tree and spine complexity but that the signaling pathways in the respective processes differ. For a more detailed characterization of these signal transduction pathways, we performed a yeast two-hybrid screen to identify proteins that interact with CALEB/NGC. Our results show that B56 beta, a regulatory subunit of protein phosphatase 2A, interacts with CALEB/NGC and inhibits CALEB/NGC-mediated dendritic branching but not spine formation. Binding of B56 beta to CALEB/NGC was confirmed by several biochemical and immunocytochemical assays. Using affinity chromatography and mass spectrometry, we demonstrate that the whole protein phosphatase 2A trimer, including structural and catalytic subunits, binds to CALEB/NGC via B56 beta. We show that CALEB/NGC induces the phosphorylation of Akt in dendrites. Previously described to interfere with Akt signaling, B56 beta inhibits Akt phosphorylation and Akt-dependent dendritic branching but not Akt-independent spine formation induced by CALEB/NGC. Our results contribute to a better understanding of signaling specificity leading to neuronal process differentiation in sequential developmental events.