Lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF)

Lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF; also called SIMPLE or PIG7) is a **monotopic zinc-binding integral membrane protein** localized primarily to the **endosomal and lysosomal compartments**. It contains a conserved C-terminal domain (the LITAF or SIMPLE-like domain), responsible for membrane integration via a hydrophobic region stabilized by adjacent zinc finger motifs[1][4]. Its N-terminal PPXY motifs enable protein-protein interactions, especially with components of the ESCRT machinery (such as TSG101 and Nedd4), promoting multivesicular body sorting and lysosomal degradation of membrane proteins[1][3][4][5][6]. LITAF is upregulated by microbial products (notably LPS) and p53, and participates in immune responses by regulating pro-inflammatory cytokines like TNF-α, among others[2][3][6]. Mutations in the LITAF gene cause the demyelinating neuropathy Charcot-Marie-Tooth disease type 1C, and altered expression is associated with cancer, obesity, and inflammatory diseases[1][6]. While considered a potential therapeutic target, there are currently no drugs directly acting on LITAF. Further research continues to elucidate its roles in endosomal trafficking, immune regulation, and disease pathology[1][2][3][4][6].

Other names

SIMPLE (Small integral membrane protein of lysosome/late endosome)PIG7 (p53-induced gene 7 protein)TP53I7 (tumor protein p53 inducible protein 7)Small integral membrane protein of the late endosomeSmall integral membrane protein of lysosome/late endosomeFLJ38636Lipopolysaccharide-induced TNF-alpha factorLPS-induced TNF-alpha factor

Not well-defined due to lack of directly interacting drugs. In theoretical or research settings, mechanisms would likely involve modulation of cytokine expression, protein trafficking, or autophagy through affecting LITAF's molecular function. Potential future approaches: small molecules or biologics targeting its interaction domains (PPXY motifs, zinc finger), its expression, or downstream signaling