Supports mycobacterial virulence via inhibition of phagosome maturation and host inducible nitric oxide synthase (iNOS) expression (PubMed:23167250). May promote the survival within macrophages by disturbing the cytokines profiles and blocking the endoplasmic reticulum (ER) stress-mediated apoptosis (PubMed:30937925). May also affect bacterial cell wall composition (PubMed:23167250). Expression in Mycobacterium smegmatis, a nonpathogenic species naturally deficient in PE_PGRS genes, results in enhanced resistance to various in vitro stresses (PubMed:30937925). It also leads to phagosome maturation arrest and increased survival in macrophages (PubMed:30937925, PubMed:23167250). Interacts with host Toll-like receptor 2 (TLR2). Exhibits vaccine potential (PubMed:18719176, PubMed:23788727). Immunogenicity is demonstrated in BALB/c mice (PubMed:18719176). Interaction with TLR2 induces activation of human dendritic cells (DCs) (PubMed:23788727). Immunization with this protein induces a significant number of CD8+ T cells and a strong Th1-type response, with high gamma interferon (IFN-gamma) and low interleukin-4 responses, and activation of the bactericidal activity of macrophages. Identified T-cell epitopes may contribute to immunity against tuberculosis if included in a vaccine (PubMed:18719176). Belongs to the mycobacterial PE family. PGRS subfamily.