Yamaji Kayoko, Tsuji Naotoshi, Miyoshi Takeharu, Hatta Takeshi, Alim M Abdul, Kushibiki Shiro, Fujisaki Kozo
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai, Tsukuba, Ibaraki 305-8572.
J Vet Med Sci. 2010 May;72(5):599-604. doi: 10.1292/jvms.09-0561. Epub 2010 Jan 26.
Although the actions of cysteine proteases are controlled in part by endogenous tight-binding cysteine protease inhibitors from the cystatin superfamily, regulatory mechanisms used by ticks to control protease activities are unknown. We report here the interaction of 2 endogenous midgut cysteine protease inhibitors, Hlcyst-1 and Hlcyst-2, with an endogenous midgut cysteine protease, HlCPL-A in Haemaphysalis longicornis. In vitro inhibition assays demonstrated that the hydrolytic activity of HlCPL-A was inhibited by Hlcyst-1 and Hlcyst-2 in dose dependent manner. Immunofluorescent studies revealed that Hlcyst-1 and Hlcyst-2 are co-localized with HlCPL-A in the epithelial cells of the midgut. The hemoglobin degradation activity of HlCPL-A was dose-dependently inhibited by Hlcyst-1 and Hlcyst-2. These results strongly indicate that, Hlcyst-1 and Hlcyst-2 are possible inhibitor of HlCPL-A and play a key role in regulatory mechanisms of hemoglobin degradation process in ticks.
尽管半胱氨酸蛋白酶的活性部分受胱抑素超家族内源性紧密结合的半胱氨酸蛋白酶抑制剂的控制，但蜱用于控制蛋白酶活性的调节机制尚不清楚。我们在此报告长角血蜱中两种内源性中肠半胱氨酸蛋白酶抑制剂Hlcyst-1和Hlcyst-2与一种内源性中肠半胱氨酸蛋白酶HlCPL-A的相互作用。体外抑制试验表明，Hlcyst-1和Hlcyst-2以剂量依赖的方式抑制HlCPL-A的水解活性。免疫荧光研究显示，Hlcyst-1和Hlcyst-2与HlCPL-A在中肠上皮细胞中共定位。Hlcyst-1和Hlcyst-2以剂量依赖的方式抑制HlCPL-A的血红蛋白降解活性。这些结果有力地表明，Hlcyst-1和Hlcyst-2可能是HlCPL-A的抑制剂，并在蜱血红蛋白降解过程的调节机制中起关键作用。
