Dos Santos Guilherme Rodrigo Rm, Rezende Leite Ana Catarina, Lander Noelia, Chiurillo Miguel Angel, Vercesi Aníbal Eugênio, Docampo Roberto
Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil.
Laboratório de Bioenergética, Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, Maceió, Brazil.
FASEB J. 2021 Jul;35(7):e21685. doi: 10.1096/fj.202100120RR.
Leucine zipper-EF-hand containing transmembrane protein 1 (Letm1) is a mitochondrial inner membrane protein involved in Ca and K homeostasis in mammalian cells. Here, we demonstrate that the Letm1 orthologue of Trypanosoma cruzi, the etiologic agent of Chagas disease, is important for mitochondrial Ca uptake and release. The results show that both mitochondrial Ca influx and efflux are reduced in TcLetm1 knockdown (TcLetm1-KD) cells and increased in TcLetm1 overexpressing cells, without alterations in the mitochondrial membrane potential. Remarkably, TcLetm1 knockdown or overexpression increases or does not affect mitochondrial Ca levels in epimastigotes, respectively. TcLetm1-KD epimastigotes have reduced growth, and both overexpression and knockdown of TcLetm1 cause a defect in metacyclogenesis. TcLetm1-KD also affected mitochondrial bioenergetics. Invasion of host cells by TcLetm1-KD trypomastigotes and their intracellular replication is greatly impaired. Taken together, our findings indicate that TcLetm1 is important for Ca homeostasis and cell viability in T cruzi.
含亮氨酸拉链-EF手型结构域的跨膜蛋白1（Letm1）是一种参与哺乳动物细胞钙和钾稳态的线粒体内膜蛋白。在此，我们证明了恰加斯病的病原体克氏锥虫的Letm1直系同源物对线粒体钙摄取和释放很重要。结果表明，在敲低TcLetm1（TcLetm1-KD）的细胞中，线粒体钙内流和外流均减少，而在过表达TcLetm1的细胞中则增加，线粒体膜电位无变化。值得注意的是，敲低或过表达TcLetm1分别会增加或不影响无鞭毛体中的线粒体钙水平。敲低TcLetm1的无鞭毛体生长减缓，过表达和敲低TcLetm1均会导致循环后期发育缺陷。敲低TcLetm1也会影响线粒体生物能量学。敲低TcLetm1的锥鞭毛体对宿主细胞的侵袭及其在细胞内的复制受到极大损害。综上所述，我们的研究结果表明TcLetm1对克氏锥虫的钙稳态和细胞活力很重要。
