Lee HyunSook, Cho Sun-Jung, Moon Il Soo
Department of Anatomy, Dongguk University College of Medicine, Gyeongju 780-714, Korea.
Mol Cells. 2014 Mar;37(3):248-56. doi: 10.14348/molcells.2014.2354. Epub 2014 Mar 12.
N-acetylglucosamine kinase (GlcNAc kinase or NAGK; EC 2.7.1.59) is a N-acetylhexosamine kinase that belong to the sugar kinase/heat shock protein 70/actin superfamily. In this study, we investigated both the expression and function of NAGK in neurons. Immunohistochemistry of rat brain sections showed that NAGK was expressed at high levels in neurons but at low levels in astrocytes. Immunocytochemistry of rat hippocampal dissociate cultures confirmed these findings and showed that NAGK was also expressed at low levels in oligodendrocytes. Furthermore, several NAGK clusters were observed in the nucleoplasm of both neuron and glia. The overexpression of EGFP- or RFP (DsRed2)-tagged NAGK in rat hippocampal neurons (DIV 5-9) increased the complexity of dendritic architecture by increasing the numbers of primary dendrites and dendritic branches. In contrast, knockdown of NAGK by shRNA resulted in dendrite degeneration, and this was prevented by the co-expression of RFP-tagged NAGK. These results suggest that the upregulation of dendritic complexity is a non-canonical function of NAGK.
N-乙酰葡糖胺激酶（GlcNAc激酶或NAGK；EC 2.7.1.59）是一种N-乙酰己糖胺激酶，属于糖激酶/热休克蛋白70/肌动蛋白超家族。在本研究中，我们调查了NAGK在神经元中的表达和功能。大鼠脑切片的免疫组织化学显示，NAGK在神经元中高水平表达，而在星形胶质细胞中低水平表达。大鼠海马解离培养物的免疫细胞化学证实了这些发现，并显示NAGK在少突胶质细胞中也低水平表达。此外，在神经元和神经胶质的核质中均观察到多个NAGK簇。在大鼠海马神经元（第5-9天）中过表达EGFP或RFP（DsRed2）标记的NAGK，通过增加初级树突和树突分支的数量，增加了树突结构的复杂性。相反，用shRNA敲低NAGK导致树突退化，而RFP标记的NAGK共表达可防止这种情况发生。这些结果表明，树突复杂性的上调是NAGK的一种非典型功能。
