Bacillus anthracis lethal factor (LF)

Bacillus anthracis lethal factor (LF) is one of three components of the anthrax toxin secreted by Bacillus anthracis—the bacterium responsible for anthrax[1][3][6]. LF is an 85-kDa zinc-dependent metalloprotease enzyme that enters host cells via complex formation with another toxin component, protective antigen (PA)[1][2][3]. Once inside, LF specifically cleaves the N-terminus of mitogen-activated protein kinase kinases (MAPKKs), thereby inhibiting critical intracellular signaling pathways. This disruption leads to lethal cellular effects, particularly rapid death of macrophages through lysis or apoptosis, and ultimately contributes to multisystem organ failure in anthrax infection[1][2][4]. LF is a validated therapeutic target for toxin-neutralizing strategies, including small-molecule inhibitors or monoclonal antibodies (none currently approved for direct human therapy)[4][6].

Other names

LFanthrax lethal factorlethal toxin factor

Zinc metalloprotease activity: LF enters host cells with the help of protective antigen, then cleaves MAPKKs inside the cytoplasm, disrupting the MAPK signaling pathway and leading to immune cell apoptosis or lysis[1][3][4].