2003/03/01 by Zulfiqar Ali Malik, Zulfiqar A Malik, Christopher R. L. Thompson +7 · 25 citations
Biochemistry, Genetics and Molecular Biology · Medicine · #Sphingolipid Metabolism and Signaling #Tuberculosis Research and Epidemiology #Calcium signaling and nucleotide metabolism
paper · doi:10.4049/jimmunol.170.6.2811
One-third of the world's population is infected with Mycobacterium tuberculosis (Mtb), and three million people die of tuberculosis each year. Following its ingestion by macrophages (MPs), Mtb inhibits the maturation of its phagosome, preventing progression to a bactericidal phagolysosome. Phagocytosis of Mtb is uncoupled from the elevation in MP cytosolic Ca(2+) that normally accompanies microbial ingestion, resulting in inhibition of phagosome-lysosome fusion and increased intracellular viability. This study demonstrates that the mechanism responsible for this failure of Ca(2+)-dependent phagosome maturation involves mycobacterial inhibition of MP sphingosine kinase. Thus, inhibition of sphingosine kinase directly contributes to survival of Mtb within human MPs and represents a novel molecular mechanism of pathogenesis.