Inhibitory effect of NAP-22 on the phosphatase activity of synaptojanin-1
Inhibitory effect of NAP-22 on the phosphatase activity of synaptojanin-1
复制标题
NAP-22 对 synaptojanin-1 磷酸酶活性的抑制作用
作者：
Takaichi;R;et al
突触囊泡的内吞作用是一个复杂的过程，有多种蛋白质和脂质参与。磷脂酰肌醇4，5-二磷酸（PIP 2）在这一过程中起着重要作用，这种脂质的动态调节是关键事件之一。Synaptojanin是一种PIP 2磷酸酶，网格蛋白包被的囊泡的PIP 2的去磷酸化导致囊泡的去包被。NAP-22是神经元抗洗涤剂膜微区的主要蛋白质之一，并且定位于突触前质膜和突触囊泡两者中。为了阐明NAP-22在突触功能中的作用，通过下拉测定进行NAP-22结合蛋白的筛选。除CapZ蛋白外，还通过LC-MS/MS检测到synaptojanin-1，使用抗synaptojanin-1的Western印迹证实了这一结果。这种相互作用在突触囊泡内吞过程中似乎很重要，因为NAP-22以剂量依赖性方式抑制synaptojanin的磷酸酶活性。NAP-22的氨基酸序列中5-磷酸酶抑制区和PIP 2结合区重叠，因此阐明NAP-22结合PIP 2能力的调节机制对于理解突触前区的膜动力学具有重要意义。© 2011 Wiley Periodicals，Inc.
Endocytosis of the synaptic vesicle is a complicated process, in which many proteins and lipids participate. Phosphatidylinositol 4,5‐bisphosphate (PIP2) plays important roles in the process, and the dynamic regulation of this lipid is one of the key events. Synaptojanin is a PIP2phosphatase, and dephosphorylation of PIP2of the clathrin coated‐vesicle results in the uncoating of the vesicle. NAP‐22 is one of the major proteins of the neuronal detergent‐resistant membrane microdomain and localizes in both the presynaptic plasma membrane and the synaptic vesicle. To elucidate the role of NAP‐22 in synaptic function, a screening of the NAP‐22 binding proteins through pull‐down assay was performed. In addition to CapZ protein, synaptojanin‐1 was detected by LC‐MS/MS, and Western blotting using antisynaptojanin‐1 confirmed this result. The interaction seems to be important in the course of synaptic vesicle endocytosis, because NAP‐22 inhibited the phosphatase activity of synaptojanin in a dose‐dependent manner. The inhibitory region for 5‐phosphatase and the binding region for PIP2overlapped in the amino acid sequence of NAP‐22, so elucidation of the regulatory mechanism of the PIP2binding ability of NAP‐22 could be important in understanding the membrane dynamics at the presynaptic region. © 2011 Wiley Periodicals, Inc.