The sequential appearance of the LSU rRNA fragments in the course of L. pneumophila an infection is suggestive of a controlled destruction of the mitochondrial ribosomes. We mapped the locations of the cleavage functions onto the predicted Haematoxylin composition of the D. discoideum LSU rRNA based on high-resolution structures of archaebacterial ribosomes. The initial cleavage function is predicted to arise on the surface of the ribosome while two secondary occasions are predicted to arise inside of the ribosomal construction. We can hypothesize two scenarios that would make the observed purchase of cleavage. The cleavage of the major website may possibly destabilize the total composition of the ribosome for the duration of translation, triggering the tiny subunit to dissociate and as a result exposing the two secondary internet sites for cleavage. Alternatively, cleavage of the main internet site could arise at any time in the translation cycle, rendering the large subunit incapable of partaking in translation or associating with the modest subunit, leaving uncovered the two websites that are generally rendered inaccessible by interactions with the little subunit. Impartial of the mechanism of cleavage, it is very likely that cleavage of the rRNA at the sites buried in regions vital to translation would abolish the normal perform of the mitochondrial ribosome.Despite the fact that the mitochondrial LSU rRNA cleavage is noticed in D. discoideum but not in A. castellanii or human host cells, it does not rule out the achievable assault by L. pneumophila on host cell mitochondria in other organisms. 1 intriguing issue remains as to the molecular route that is exploited to assault the host cells’ mitochondria. Are physical contacts among the pathogencontaining phagosome and host mobile mitochondria required, or do L. pneumophila proteins secreted into the cytoplasm exploit the standard mitochondrial import equipment of the host We analyzed for rRNA cleavage in D. discoideum cluA mutants, which have a phenotype of abnormal distribution of tightly clustered mitochondria [57]. The clustered mitochondria would be predicted to preclude interactions with other organelles because the mitochondria are in near apposition with each and every other in this mutant. Relatively 
astonishingly, we detected a similar level of rRNA cleavage in infected cluA mutant cells and in wild-kind cells (unpublished observations). This implies that the possible bacterial proteins liable for the cleavage require not be sent to the host cell mitochondria via immediate affiliation with the 23086298pathogen-made up of phagosome, or replicative vacuole.