Pace Karen E, Lebestky Tim, Hummel Thomas, Arnoux Pascal, Kwan Kent, Baum Linda G
Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California 90095, USA.
J Biol Chem. 2002 Apr 12;277(15):13091-8. doi: 10.1074/jbc.M112105200. Epub 2002 Jan 24.
We have cloned and characterized the first galectin to be identified in Drosophila melanogaster. The amino acid sequence of Drosophila galectin showed striking sequence similarity to invertebrate and vertebrate galectins and contained amino acids that are crucial for binding beta-galactoside sugars. Confirming its identity as a galectin family member, the Drosophila galectin bound beta-galactoside sugars. Structurally, the Drosophila galectin was a tandem repeat galectin containing two carbohydrate recognition domains connected by a unique peptide link. This divalent structure suggests that like mammalian galectins, Drosophila galectin may mediate cell-cell communication or facilitate cross-linking of receptors to trigger signal transduction events. The Drosophila galectin was very abundant in embryonic, larval, and adult Drosophila. During embryogenesis, Drosophila galectin had a unique and specific tissue distribution. Drosophila galectin expression was concentrated in somatic and visceral musculature and in the central nervous system. Similar to other insect lectins, Drosophila galectin may function in both embryogenesis and in host defense. Drosophila galectin was expressed by hemocytes, circulating phagocytic cells, suggesting a role for Drosophila galectin in the innate immune system.
我们已经克隆并鉴定了在黑腹果蝇中发现的首个半乳糖凝集素。果蝇半乳糖凝集素的氨基酸序列与无脊椎动物和脊椎动物的半乳糖凝集素显示出显著的序列相似性，并且包含对结合β-半乳糖苷糖至关重要的氨基酸。果蝇半乳糖凝集素与β-半乳糖苷糖结合，证实了其作为半乳糖凝集素家族成员的身份。在结构上，果蝇半乳糖凝集素是一种串联重复半乳糖凝集素，包含两个通过独特肽链连接的碳水化合物识别结构域。这种二价结构表明，与哺乳动物半乳糖凝集素一样，果蝇半乳糖凝集素可能介导细胞间通讯或促进受体交联以触发信号转导事件。果蝇半乳糖凝集素在胚胎、幼虫和成虫果蝇中含量非常丰富。在胚胎发育过程中，果蝇半乳糖凝集素有独特而特异的组织分布。果蝇半乳糖凝集素的表达集中在体壁和内脏肌肉组织以及中枢神经系统中。与其他昆虫凝集素相似，果蝇半乳糖凝集素可能在胚胎发育和宿主防御中都发挥作用。果蝇半乳糖凝集素由血细胞（循环吞噬细胞）表达，这表明果蝇半乳糖凝集素在先天免疫系统中发挥作用。
