Okulate M A, Kalume D E, Reddy R, Kristiansen T, Bhattacharyya M, Chaerkady R, Pandey A, Kumar N
Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Insect Mol Biol. 2007 Dec;16(6):711-22. doi: 10.1111/j.1365-2583.2007.00765.x.
Molecular mechanisms underlying the interaction between malarial sporozoites and putative receptor(s) on the salivary glands of Anopheles gambiae remain largely unknown. In previous studies, a salivary gland protein of ~100 kDa was identified as a putative target based on recognition of the protein by a monoclonal antibody (mAb) 2A3 that caused a >/= 70% reduction in the average number of sporozoites per infected salivary gland when fed to mosquitoes. Using affinity purification we purified the target of this mAb from extracts of female A. gambiae salivary glands and it was found to be a novel protein by tandem mass spectrometric analysis. Biochemical and molecular characterization of the 100 kDa protein showed that this molecule, designated Saglin, exists as a disulphide-bonded homodimer of 50 kDa subunits. The ability to form homodimers was retained even in the recombinant Saglin expressed in mammalian cells (HEK293). The amino acid sequence of Saglin contains a signal peptide suggesting that Saglin is a secreted protein. If Saglin is indeed involved in the process of invasion of A. gambiae salivary glands by sporozoites of Plasmodium, it could provide a novel target for future investigations aimed at interruption of malaria transmission.
冈比亚按蚊唾液腺中的疟原虫子孢子与假定受体之间相互作用的分子机制在很大程度上仍然未知。在先前的研究中，一种约100 kDa的唾液腺蛋白被确定为假定靶点，这是基于一种单克隆抗体（mAb）2A3对该蛋白的识别，当将其喂给蚊子时，每个受感染唾液腺中的子孢子平均数量减少了≥70%。我们利用亲和纯化从冈比亚按蚊雌蚊唾液腺提取物中纯化了该单克隆抗体的靶点，并通过串联质谱分析发现它是一种新蛋白。对100 kDa蛋白的生化和分子特性分析表明，该分子命名为Saglin，以50 kDa亚基的二硫键连接同型二聚体形式存在。即使在哺乳动物细胞（HEK293）中表达的重组Saglin中，形成同型二聚体的能力也得以保留。Saglin的氨基酸序列包含一个信号肽，表明Saglin是一种分泌蛋白。如果Saglin确实参与了疟原虫子孢子侵入冈比亚按蚊唾液腺的过程，那么它可能为未来旨在阻断疟疾传播的研究提供一个新的靶点。
