Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht St. 74, 20359, Hamburg, Germany.
Cell Stress Chaperones. 2010 Jul;15(4):443-55. doi: 10.1007/s12192-009-0160-7. Epub 2009 Dec 2.
Molecular chaperone proteins play a pivotal role in the protozoan parasite Leishmania donovani, controlling cell fate and ensuring intracellular survival. In higher eukaryotes, the so-called co-chaperone proteins are required for client protein recognition and proper function of chaperones, among them the small glutamine-rich tetratricopeptide repeat proteins (SGT) which interact with both HSP70 and HSP90 chaperones. An atypical SGT homolog is found in the L. donovani genome, encoding a protein lacking the C-terminal glutamine-rich region, normally typical for SGT family members. The gene is expressed constitutively during the life cycle and is essential for survival and/or growth of the parasites. LdSGT forms large, stable complexes that also include another putative co-chaperone, HSC70 interacting protein (HIP). The gene product forms cytoplasmic clusters, matching the subcellular distribution of HIP and partly that of the major cytoplasmic chaperones, HSP70 and HSP90, reflecting a direct molecular interaction with both chaperones.
分子伴侣蛋白在原生动物寄生虫利什曼原虫中起着至关重要的作用，控制着细胞命运并确保细胞内的存活。在高等真核生物中，所谓的共伴侣蛋白对于识别靶蛋白和伴侣蛋白的正常功能是必需的，其中包括与 HSP70 和 HSP90 伴侣蛋白相互作用的小谷氨酰胺富含四肽重复蛋白（SGT）。在利什曼原虫基因组中发现了一种非典型的 SGT 同源物，它编码的蛋白缺乏 C 末端富含谷氨酰胺的区域，这通常是 SGT 家族成员的典型特征。该基因在生命周期中持续表达，对于寄生虫的存活和/或生长是必需的。LdSGT 形成大的、稳定的复合物，还包括另一种假定的共伴侣蛋白，HSC70 相互作用蛋白（HIP）。该基因产物形成细胞质簇，与 HIP 的亚细胞分布部分匹配，与主要细胞质伴侣蛋白 HSP70 和 HSP90 的亚细胞分布部分匹配，反映了与这两种伴侣蛋白的直接分子相互作用。
