Expression and subcellular localization of cpn60 protein family members in Leishmania donovani.

We have identified two diverged members of the cpn60 gene family in Leishmania donovani, causative agent of Indian Kala Azar. One of the genes, cpn60.1, although actively transcribed, is not expressed to detectable levels of protein in cultured L. donovani. The other gene, cpn60.2, which, compared with cpn60.1, shows a higher sequence conservation with the hsp60 genes from Trypanosoma brucei and Trypanosoma cruzi is expressed constitutively in cultured promastigotes. The abundance of the gene product, Cpn60.2, increases by 2.5-fold under heat stress and in axenic amastigotes of L. donovani. Cpn60.2 is also found enriched in mitochondrial cell fractions and localizes to the mitochondrial matrix. We conclude that Cpn60.2 is the major mitochondrial chaperonin in Leishmania.