Chen et al. describe how TMX2, a thioredoxin-related transmembrane protein, moderates oxidative conditions at the endoplasmic reticulum-mitochondria contact site (ERMCS). This allows TMX2 to limit mit...

Thioredoxins are ubiquitous redox proteins that are found in all domains of life. These conserved proteins are also found in many phages, including marine cyanophages that infect the ecologically important marine cyanobacteria. However, their role in phage infection is not known. Cyanophages also carry many small genes lacking homology to known functional domains. Whether these have a functional role or not remains unknown. Here, we explore the distribution and role of a cyanophage thioredoxin (trxA), and that of a small gene directly downstream of it (g26), in phage infection. For this we used the T7-like cyanophage, Syn5, which infects an open-ocean marine Synechococcus strain, WH8109. We found that thioredoxin genes are common in phage genomes, including in cyanophages. The g26 gene, however, is restricted in it distribution to the cyanophages. The cyanophage thioredoxin is catalytically active and it increases phage DNA replication, progeny production and competitive fitness. It also negatively impacts host growth. The g26 gene product is translationally coupled to, and thus dependent on, translation of the thioredoxin gene. This gene itself significantly increases phage virulence and fitness, yet reduces burst size. Our findings demonstrate that cyanophage thioredoxins impact phage fitness and infection physiology and that small viral genes with no homology to known genes can play an important role in the infection process. These findings provide insights into the importance of unusual genes in phage genomes and show that they are likely to play an important role in the interactions between abundant cyanobacteria and cyanophages in ocean ecosystems. ### Competing Interest Statement The authors have declared no competing interest.

Redox regulators are emerging as critical mediators of lung tumorigenesis. NRF2 and its negative regulator KEAP1 are commonly mutated in human lung ca…

Ferredoxin-dependent flavin thioredoxin reductases (FFTRs) regenerate reduced thioredoxin, sustaining dithiol–disulfide exchange reactions that regulate protein activity in select organisms. In cyano...

PhD Project - MRC DiMeN Doctoral Training Partnership: Targeting thioredoxin reductase to combat antifungal resistance in Candida spp. at Newcastle University, listed on FindAPhD.com

A redox-dependent post-translational modification mechanism fine-tunes the activity of phosphoglycolate phosphatase, which catalyzes the initial step of the photorespiratory pathway, the conversion o...

Abstract. Previous studies suggest that the synthesis of glutamate/glutamine is regulated by the mitochondrial thioredoxin (TRX) system. However, the mecha

Proteasomes degrade diverse proteins in different cellular contexts through incompletely defined regulatory mechanisms. Here, we report the cryo-EM structure of thioredoxin-like protein 1 (TXNL1) boun...

Ferredoxin-dependent flavin thioredoxin reductases (FFTRs) regenerate reduced thioredoxin, sustaining dithiol–disulfide exchange reactions that regulate protein activity in select organisms. In cyano...

The thioredoxin (Trx) system, an ancestral and ubiquitous mechanism, maintains thiol homeostasis. The prolonged co-evolution of this system with bacteria has resulted in a broad spectrum of physiolog...

The thioredoxin system is key for cellular redox control and a target for several therapeutic principles but is difficult to study because of methodological limitations. Here, we present chemical design principles for developing probes reporting on the activities of the enzymes in this system, within live cells. Additionally, we assess existing literature, including published validation experiments, and highlight concerns regarding the performance of some probes. Finally, we present an experimental pipeline for future probe development.

Pseudomonas aeruginosa, an opportunistic human pathogen, is known for its ability to respond and adapt to its environment, employing intricate adaptat…

Abstract. Under natural growth conditions, plants are constantly exposed to changes in light intensity. PROTON GRADIENT REGULATION 5 (PGR5)-dependent photo

Abstract. Glutaredoxins (GRXs) constitute a distinct family within the large thioredoxin superfamily. Based on the historic order of discoveries and struct