Ohsawa K, Imai Y, Ito D, Kohsaka S
Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan.
J Neurochem. 1996 Jul;67(1):89-97. doi: 10.1046/j.1471-4159.1996.67010089.x.
We previously reported that annexin V promoted the survival of cultured rat neocortical neurons. In an effort to elucidate the mechanism underlying this neurotrophic activity of annexin V, we have attempted to identify the target or binding proteins of annexin V in neuronal cells. Herein, we screened an embryonic day 17 rat brain cDNA library by western blot using glutathione S-transferase-annexin V fusion protein as a probe and then isolated four clones showing binding to annexin V in a Ca2+ - and phospholipid-dependent manner. Although these cDNAs encoded different polypeptides, all four polypeptides shared the unique feature of containing highly hydrophilic stretches with high Lys, Glu, and Ser contents. Deduced amino acid sequences of two clones showed high homology with human X-linked Helicase2 (XH2) and DNA (cytosine-5) methyltransferase (DMTase) sequences, whereas the other two were not related to any known peptide sequence. These results suggest that XH2 and DMTase are candidates for annexin V-binding proteins and thus may mediate the biological activity of annexin V.
我们先前报道过，膜联蛋白V可促进培养的大鼠新皮质神经元存活。为阐明膜联蛋白V这种神经营养活性的潜在机制，我们试图鉴定神经元细胞中膜联蛋白V的靶蛋白或结合蛋白。在此，我们以谷胱甘肽S-转移酶-膜联蛋白V融合蛋白为探针，通过蛋白质印迹法筛选胚胎第17天大鼠脑cDNA文库，随后分离出四个以Ca2+和磷脂依赖方式与膜联蛋白V结合的克隆。尽管这些cDNA编码不同的多肽，但所有四种多肽都具有包含高赖氨酸、谷氨酸和丝氨酸含量的高度亲水区段这一独特特征。两个克隆的推导氨基酸序列与人X连锁解旋酶2（XH2）和DNA（胞嘧啶-5）甲基转移酶（DMTase）序列高度同源，而另外两个与任何已知肽序列均无关联。这些结果表明，XH2和DMTase是膜联蛋白V结合蛋白的候选者，因此可能介导膜联蛋白V的生物学活性。
