Conservation of Putative Liquid–Liquid Phase Separating Proteins in Multiple Drug-Resistant <i>Mycobacterium tuberculosis</i>: Role in Host–Pathogen Interactions?

We observed a high proportion of proteins in pathogenic Mycobacterium species that can potentially undergo liquid–liquid phase separation (LLPS) mediated biomolecular condensate formation, compared to nonpathogenic species. These proteins mainly include the PE-PPE and PE-PGRS families of proteins that have nucleic acid and protein–protein binding functions, typical of LLPS proteins. We also mapped identified LLPS proteins in M. tuberculosis (M.tb) drug-resistant databases PubMLST and TBProfiler, based upon the WHO 2023 catalogue of resistance-associated mutations. High sequence conservation of LLPS-associated proteins in various multiple drug-resistant M.tb isolates points to their potentially important role in virulence and host–pathogen interactions during pathogenic evolution. This analysis provides a perspective on the role of protein phase separation in the evaluation of M.tb pathogenesis and offers avenues for future research aimed at developing innovative strategies to combat M.tb infection.