Service de Biochimie A, Hôpital Saint-Antoine, AP-HP, 75012, Paris, France.
Naunyn Schmiedebergs Arch Pharmacol. 2011 Oct;384(4-5):407-19. doi: 10.1007/s00210-011-0639-5. Epub 2011 May 4.
NME/NDPK family proteins are involved in the control of intracellular nucleotide homeostasis as well as in both physiological and pathological cellular processes, such as proliferation, differentiation, development, apoptosis, and metastasis dissemination, through mechanisms still largely unknown. One family member, NME1/NDPK-A, is a metastasis suppressor, yet the primary physiological functions of this protein are still missing. The purpose of this study was to identify new NME1/NDPK-A-dependent biological functions and pathways regulated by this gene in the liver. We analyzed the proteomes of wild-type and transgenic NME1-null mouse livers by combining two-dimensional gel electrophoresis and mass spectrometry (matrix-assisted laser desorption/ionization time of flight and liquid chromatography-tandem mass spectrometry). We found that the levels of three proteins, namely, phenylalanine hydroxylase, annexin IV, and elongation factor 1 Bα (EF-1Bα), were strongly reduced in the cytosolic fraction of NME1(-/-) mouse livers when compared to the wild type. This was confirmed by immunoblotting analysis. No concomitant reduction in the corresponding messenger RNAs or of total protein level was observed, however, suggesting that NME1 controls annexin IV and EF-1Bα amounts by post-translational mechanisms. NME1 deletion induced a change in the subcellular location of annexin IV in hepatocytes resulting in enrichment of this protein at the plasma membrane. We also observed a redistribution of EF-1Bα in NME1(-/-) hepatocytes to an intracytoplasmic compartment that colocalized with a marker of the reticulum endoplasmic. Finally, we found reduced expression of annexin IV coincident with decreased NME1 expression in a panel of different carcinoma cell lines. Taken together, our data suggest for the first time that NME1 might regulate the subcellular trafficking of annexin IV and EF-1Bα. The potential role of these proteins in metastatic dissemination is discussed.
NME/NDPK 家族蛋白参与细胞内核苷酸动态平衡的控制，以及增殖、分化、发育、凋亡和转移扩散等生理和病理细胞过程，但其机制在很大程度上尚不清楚。家族成员之一 NME1/NDPK-A 是一种转移抑制因子，但该蛋白的主要生理功能仍不清楚。本研究旨在鉴定新的 NME1/NDPK-A 依赖的生物学功能和受该基因调控的肝脏途径。我们通过二维凝胶电泳和质谱（基质辅助激光解吸/电离飞行时间和液相色谱-串联质谱）相结合，分析了野生型和转基因 NME1 缺失型小鼠肝脏的蛋白质组。我们发现，与野生型相比，NME1(-/-) 小鼠肝脏胞质部分中三种蛋白质（苯丙氨酸羟化酶、膜联蛋白 IV 和延伸因子 1Bα (EF-1Bα)）的水平显著降低。免疫印迹分析证实了这一点。然而，没有观察到相应信使 RNA 或总蛋白水平的伴随减少，这表明 NME1 通过翻译后机制控制膜联蛋白 IV 和 EF-1Bα 的含量。NME1 缺失诱导膜联蛋白 IV 在肝细胞中的亚细胞位置发生变化，导致该蛋白在质膜处富集。我们还观察到 EF-1Bα 在 NME1(-/-) 肝细胞中的重新分布到一个细胞内隔室，该隔室与内质网的标记物共定位。最后，我们发现不同癌系细胞中 annexin IV 的表达与 NME1 表达的减少同时减少。综上所述，我们的数据首次表明，NME1 可能调节膜联蛋白 IV 和 EF-1Bα 的细胞内运输。讨论了这些蛋白质在转移扩散中的潜在作用。
