Human GBP4 promotes TRIM21-BIP-dependent autophagy to restrict M. tuberculosis infection by preventing SORT1-mediated progranulin degradation

Interferons (IFNs) are potent antimicrobial cytokines. However, effector mechanisms mediating their function in humans are poorly understood, partly because IFNs can induce numerous effector molecules. While guanylate-binding proteins (GBPs) are IFN-inducible, their role in cell-autonomous resistance to intracellular pathogens is incompletely understood. We demonstrate that human GBP1-5 significantly inhibits intracellular Mycobacterium tuberculosis (Mtb) survival, but only GBP4 mediates autophagy. GBP4 facilitates Mtb containment by promoting lysosomal acidification and autophagy via type Ⅰ IFN-dependent TFEB and FOXO3a activation. Mechanistically, GBP4 binds progranulin (GRN), reducing SORT1-mediated GRN lysosomal degradation. Moreover, GBP4 facilitates the GBP4-GRN-BIP-AKT complex assembly while inhibiting the GBP4-BIP-TRIM21 complex formation, thereby enhancing GRN-mediated BIP accumulation and AKT degradation. This leads to AKT inhibition, and concomitant TFEB and FOXO3a activation. GRN, BIP, AKT, and TRIM21 are essential for GBP4-mediated mycobactericidal activity. Our study uncovers a key role for GBP4 in regulating cell-autonomous resistance in human macrophages and may facilitate the development of host-directed therapies against tuberculosis (TB).