Kurucz Eva, Zettervall Carl-Johan, Sinka Rita, Vilmos Peter, Pivarcsi Andor, Ekengren Sophia, Hegedüs Zoltán, Ando Istvan, Hultmark Dan
Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, P.O Box 521, H-6701 Szeged, Hungary. Umeå Centre for Molecular Pathogenesis, By. 6L, Umeå University, S-901 87 Umeå, Sweden.
Proc Natl Acad Sci U S A. 2003 Mar 4;100(5):2622-7. doi: 10.1073/pnas.0436940100. Epub 2003 Feb 21.
We have identified a previously undescribed transmembrane protein, Hemese, from Drosophila melanogaster blood cells (hemocytes), by using a monoclonal pan-hemocyte antibody. Heavy glycosylation is suggested by the heterogeneous size distribution, ranging between 37 and 70 kDa. Hemese expression is restricted to the cell surfaces of hemocytes of all classes, and to the hematopoietic organs. The sequence of the corresponding gene, Hemese (He), predicts a glycophorin-like protein of 15 kDa, excluding an N-terminal signal peptide, with a single hydrophobic transmembrane region. The extracellular region consists mainly of Ser/Thr-rich sequence of low complexity, with several potential O-glycosylation sites. Hemese contains phosphotyrosine and the cytoplasmic region has potential phosphorylation sites, suggesting an involvement in signal transduction. Depletion of Hemese by RNA interference has no obvious effect under normal conditions, but the cellular response to parasitic wasps is much enhanced. This finding indicates that Hemese plays a modulatory role in the activation or recruitment of the hemocytes.
我们通过使用一种单克隆全血细胞抗体，从黑腹果蝇血细胞中鉴定出一种此前未被描述的跨膜蛋白——血膜蛋白（Hemese）。其大小分布不均一，介于37至70 kDa之间，提示存在高度糖基化。血膜蛋白的表达仅限于所有类型血细胞的细胞表面以及造血器官。相应基因血膜蛋白（He）的序列预测，去除N端信号肽后，它是一种15 kDa的类血型糖蛋白，具有一个单一的疏水跨膜区域。细胞外区域主要由低复杂性的富含丝氨酸/苏氨酸的序列组成，有几个潜在的O-糖基化位点。血膜蛋白含有磷酸酪氨酸，其细胞质区域有潜在的磷酸化位点，提示其参与信号转导。在正常条件下，通过RNA干扰使血膜蛋白缺失没有明显影响，但血细胞对寄生蜂的细胞反应显著增强。这一发现表明，血膜蛋白在血细胞的激活或募集过程中起调节作用。
