SLC46A2 is a proton-coupled transporter that delivers pathogen-associated molecular patterns (PAMPs) to cytosolic pattern recognition receptors as part of innate immune defense 1. The transporter exhibits selectivity for DAP-type peptidoglycan muropeptides (including tracheal cytotoxin) common in Gram-negative bacteria and bacilli, transporting these across endolysosomal membranes into the cytosol for NOD1 recognition, triggering MYD88-dependent IL1A secretion and neutrophil recruitment 12. SLC46A2 also redundantly transports muramyl dipeptides to activate NOD2 signaling 1. In immune cells, SLC46A2 functions as the dominant importer of cyclic GMP-AMP dinucleotides (cGAMPs) in monocytes and M1-polarized macrophages, selectively importing pathogenic bacterial cGAMPs (3'3'-cGAMP) to provide differential immune recognition between pathogenic and commensal bacteria 3. During tumorigenesis, SLC46A2 imports tumor-derived 2'3'-cGAMP across plasma membranes to activate STING pathway-mediated anti-tumor immunity 3. HSV-1 antagonizes SLC46A2 function by targeting it for proteasomal degradation via the UL56 protein, thereby inhibiting intercellular cGAMP transfer and limiting innate antiviral immunity 4. Dysregulation of SLC46A2 has been associated with psoriasis pathogenesis and lung squamous cell carcinoma metastasis 56.