Lipoarabinomannan regulates septation in Mycobacterium smegmatis .

Mycobacteria cause many diseases including tuberculosis (TB). Lipoarabinomannan (LAM) is a lipoglycan of mycobacteria and related bacteria, playing important roles as a surface-exposed pathogen-associated molecular pattern during host-pathogen interactions. Its importance is highlighted by the facts that anti-LAM antibody appears to be protective against TB disease progression, and urine LAM serves as a diagnostic marker for active TB. Given the clinical and immunological relevance of the molecule, it was a striking gap in knowledge that we did not know the cellular function of this lipoglycan in mycobacteria. In this study, we demonstrated that LAM regulates septation, a principle potentially generalizable to other lipoglycans widely found in a group of Gram-positive bacteria that lack lipoteichoic acids.