Saveria Tracy, Kessler Peter, Jensen Bryan C, Parsons Marilyn
Seattle Biomedical Research Institute, 307 Westlake Avenue N., Seattle, WA 98109, USA.
Exp Parasitol. 2007 May;116(1):14-24. doi: 10.1016/j.exppara.2006.11.004. Epub 2006 Dec 26.
The glycosomes of trypanosomatids are essential organelles that are evolutionarily related to peroxisomes of other eukaryotes. The peroxisomal RING proteins-PEX2, PEX10 and PEX12-comprise a network of integral membrane proteins that function in the matrix protein import cycle. Here, we describe PEX10 and PEX12 in Trypanosoma brucei, Leishmania major, and Trypanosoma cruzi. We expressed GFP fusions of each T. brucei coding region in procyclic form T. brucei, where they localized to glycosomes and behaved as integral membrane proteins. Despite the weak transmembrane predictions for TbPEX12, protease protection assays demonstrated that both the N and C termini are cytosolic, similar to mammalian PEX12. GFP fusions of T. cruzi PEX10 and L. major PEX12 also localized to glycosomes in T. brucei indicating that glycosomal membrane protein targeting is conserved across trypanosomatids.
锥虫的糖体是重要的细胞器，在进化上与其他真核生物的过氧化物酶体相关。过氧化物酶体环状蛋白PEX2、PEX10和PEX12构成了一个整合膜蛋白网络，在基质蛋白导入循环中发挥作用。在这里，我们描述了布氏锥虫、硕大利什曼原虫和克氏锥虫中的PEX10和PEX12。我们在原循环型布氏锥虫中表达了每个布氏锥虫编码区的绿色荧光蛋白（GFP）融合蛋白，它们定位于糖体并表现为整合膜蛋白。尽管对TbPEX12的跨膜预测较弱，但蛋白酶保护试验表明，其N端和C端均位于胞质中，这与哺乳动物的PEX12相似。克氏锥虫PEX10和硕大利什曼原虫PEX12的GFP融合蛋白也定位于布氏锥虫的糖体，这表明糖体膜蛋白靶向在整个锥虫中是保守的。
