Biology subjects

Adcox, H.

Publications and source records attributed to Adcox, H..

2 recordsLinked to original sources

bioRxiv2026

Intracellular pathogen targeting by IL32 elicits cell-autonomous immunity

Interferon-{gamma} safeguards humans against intracellular pathogens, yet how most interferon-stimulated genes protect host cells, and how human-adapted pathogens evade these defenses is unclear1,2. Here, we discover a potent immune surveillance and effector circuit executed by an intracellularly acting cytokine, IL32, that targets and restricts phylogenetically distinct vacuolar pathogens, including the bacterium Chlamydia and the microsporidian Encephalitozoon. Quantitative proteomics coupled to a tailored CRISPR screen, uncovered components of the cysteine/Arg N-degron pathway3 that modify IL32 through oxidation-dependent arginylation, thereby enabling the recruitment of the autophagy machinery to pathogen-containing vacuoles. A forward genetics screen in Chlamydia trachomatis, the leading cause of sexually transmitted bacterial infection, identified the secreted virulence factor IncS as an evasion factor that blocks IL32 targeting and shields this human pathogen from xenophagy. These findings establish an IL32-dependent intracellular sensing mechanism linking IFN{gamma} signaling to N-degron-mediated xenophagy, revealing a broadly relevant axis of human host-pathogen conflict.

immunology↗

bioRxiv2023

Orientia tsutsugamushi Ank5 directs ubiquitination and proteasomal degradation of NLRC5 to inhibit major histocompatibility complex class I expression

How intracellular bacteria subvert the major histocompatibility complex (MHC) class I pathway is poorly understood. Here, we show that the obligate intracellular bacterium Orientia tsutsugamushi uses its effector protein, Ank5, to orchestrate proteasomal degradation of the MHC class I gene transactivator, NLRC5. Ank5 uses a tyrosine in its fourth ankyrin repeat to bind the NLRC5 N-terminus while its F-box directs host SCF complex ubiquitination of K1194 in the leucine-rich repeat region that dictates NLRC5 susceptibility to Orientia- and Ank5-mediated degradation. The ability of O. tsutsugamushi strains to degrade NLRC5 correlates with ank5 genomic carriage. Ectopically expressed Ank5 that can bind but not degrade NLRC5 protects the transactivator during Orientia infection. Thus, Ank5 is an immunoevasin that uses its bipartite architecture to rid host cells of NLRC5 and MHC class I molecules. This study offers insight into how intracellular pathogens can impair MHC class I expression to benefit their survival.

microbiology↗