Division of Biochemistry, Department of Molecular Cell Biology, Faculty of Medicine, KULeuven, B-3000, Leuven, Belgium,
Purinergic Signal. 2006 Jun;2(2):361-70. doi: 10.1007/s11302-005-5303-4. Epub 2006 Jun 1.
Extracellular nucleotides can elicit a wide array of cellular responses by binding to specific purinergic receptors. The level of ectonucleotides is dynamically controlled by their release from cells, synthesis by ectonucleoside diphosphokinases and ectoadenylate kinases, and hydrolysis by ectonucleotidases. One of the four structurally unrelated families of ectonucleotidases is represented by the NPP-type ectophosphodiesterases. Three of the seven members of the NPP family, namely NPP1-3, are known to hydrolyze nucleotides. The enzymatic action of NPP1-3 (in)directly results in the termination of nucleotide signaling, the salvage of nucleotides and/or the generation of new messengers like ADP, adenosine or pyrophosphate. NPP2 is unique in that it hydrolyzes both nucleotides and lysophospholipids and, thereby, generates products that could synergistically promote cell motility. We review here the enzymatic properties of NPPs and analyze current evidence that links their nucleotide-hydrolyzing capability to epithelial and neural functions, the immune response and cell motility.
细胞外核苷酸可以通过与特定的嘌呤能受体结合来引发广泛的细胞反应。细胞外核苷酸的水平通过它们从细胞中的释放、由胞苷二磷酸激酶和腺苷酸激酶合成以及由胞外核苷酸酶水解来动态控制。四种结构上无关的胞外核苷酸酶家族之一是 NPP 型磷酸二酯酶。NPP 家族的七个成员中的三个，即 NPP1-3，已知可以水解核苷酸。NPP1-3 的酶促作用（直接或间接）导致核苷酸信号的终止、核苷酸的回收和/或新信使如 ADP、腺苷或焦磷酸的产生。NPP2 的独特之处在于它可以水解核苷酸和溶血磷脂，从而产生协同促进细胞运动的产物。我们在这里回顾了 NPP 的酶学特性，并分析了将其核苷酸水解能力与上皮和神经功能、免疫反应和细胞运动联系起来的现有证据。
