Identification and characterization of nCLP2, a novel C1q family protein expressed in the central nervous system
Identification and characterization of nCLP2, a novel C1q family protein expressed in the central nervous system
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DOI：
10.1093/jb/mvp203
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发表时间：
2010-04-01
影响因子：
2.7
通讯作者：
Sekiguchi, Kiyotoshi
中科院分区：
文献类型：
--
作者：
Shimono, Chisei;Manabe, Ri-ichiroh;Sekiguchi, Kiyotoshi
C1 q家族的特征在于C-末端保守的球状C1 q（gC 1 q）结构域。尽管在哺乳动物中已经鉴定了30多种C1 q家族蛋白，但其中许多蛋白的分子和生物学特性仍不清楚。在这里，我们报告了一种新的C1 q家族蛋白特异性表达于中枢神经系统（CNS），我们指定神经C1 q样蛋白（nCLP）2。nCLP 2作为包含三聚体单元的二硫键键合的多聚体分泌。多聚体通过涉及N-末端可变区和C-末端gC 1 q结构域中的半胱氨酸残基的链间二硫键来稳定。nCLP 2的表达仅限于几个脑区和视网膜，包括与记忆形成相关的区域（即海马、内嗅皮层、丘脑前背核）。免疫电镜显示nCLP 2定位于海马颗粒细胞苔藓纤维轴突及其突触终扣和裂隙中，这意味着nCLP 2在苔藓纤维中顺行运输并从突触前末端分泌。这些结果表明，nCLP 2在CNS中的突触功能和维持中起作用。
The C1q family is characterized by the C-terminally conserved globular C1q (gC1q) domain. Although more than 30 C1q family proteins have been identified in mammals, many of them remain ill-defined with respect to their molecular and biological properties. Here, we report on a novel C1q family protein specifically expressed in the central nervous system (CNS), which we designated neural C1q-like protein (nCLP) 2. nCLP2 was secreted as disulphide-bonded multimers comprising trimeric units. The multimers were stabilized by interchain disulphide bonds involving the cysteine residues in the N-terminal variable region and the C-terminal gC1q domain. The expression of nCLP2 was restricted to several brain regions and retina, including regions associated with memory formation (i.e. hippocampus, entorhinal cortex, anterodorsal thalamic nucleus). Immunoelectron microscopy revealed that nCLP2 was localized in the mossy fibre axons of hippocampal granule cells and their synaptic boutons and clefts, implying that nCLP2 was anterogradely transported in mossy fibres and secreted from the presynaptic termini. These results suggest that nCLP2 plays roles in synaptic function and maintenance in the CNS.