From guide to guard-activation mechanism of the stress-sensing chaperone Get3.

Oxidative stress conditions can cause ATP depletion, oxidative protein unfolding, and potentially toxic protein aggregation. To alleviate this proteotoxic stress, the highly conserved yeast protein, Get3, switches from its guiding function as an ATP-dependent targeting factor for tail-anchored proteins to its guarding function as an ATP-independent molecular chaperone that prevents irreversible protein aggregation. Here, we demonstrate that activation of Get3's chaperone function follows a tightly orchestrated multi-step process, centered around the redox status of two conserved cysteines, whose reactivity is directly controlled by Get3's nucleotide-binding state. Thiol oxidation causes local unfolding and the transition into chaperone-active oligomers. Vice versa, inactivation requires the reduction of Get3's cysteines followed by ATP-binding, which allows the transfer of bound client proteins to ATP-dependent chaperone systems for their effective refolding. Manipulating this fine-tuned cycle of activation and inactivation in yeast impairs oxidative stress resistance and growth, illustrating the necessity to tightly control Get3's intrinsic chaperone function.

Psychological interventions in the treatment of delusional parasitosis: a brief review.

This review synthesized evidence on the most up-to-date treatment outcomes in patients with delusional parasitosis and examined the impact of incorporating psychological interventions in conjunction with psychiatric treatment. The reporting of this review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. PubMed and Google Scholar were searched between 2013 and 2023. Nine studies were included in this review. Partial remission was observed across all cases, irrespective of the treatment approach employed. Complete remission was limited to only three studies. No correlation was observed between the incorporation of psychological intervention in conjunction with psychotropic medication and an enhanced remission outcome. The findings underscore the importance of psychotropic medication as a fundamental component in the treatment of delusional parasitosis. The results highlight that although first- and second-generation psychotropic medications are the mainstay treatment options, they nevertheless play a limited role because of the patients' steadfast delusions of infestations.

Psychodermatology of Chronic Pruritus: An Overview of the Link Between Itch and Distress.

Chronic pruritus (CP) is defined as an unpleasant sensation causing a desire to scratch and lasting > 6 weeks. It has a multifactorial etiology but is more frequently associated with chronic inflammatory dermatoses and systemic disorders. Psychogenic pruritus and neurological disorders are other less common etiologies, while, in some patients, it is idiopathic. CP appears to be processed by non-histaminergic pathway, contributing to its complexity and therapeutic challenge. Moreover, regardless of the etiology, it is multidimensional, including cognitive, motivational and affective components. There is a close link between psychological distress and pruritus, with particular clinical expression in chronic inflammatory dermatoses, involving the activation of the hypothalamic-pituitary-adrenal axis (and its cutaneous equivalent), the sympathetic nervous system, the release of hormones and peptides, the role of immune cells (T and B cells, macrophages) and immune-related cells in the skin (mast cells, dendritic cells and keratinocytes). Moreover, there is strong evidence that psychological factors influence the experience of pruritus. CP can also cause psychiatric disorders, including but not limited to anxiety and depression, and also lead to significant quality of life (QoL) impairment. Thereby, although a psychodermatological assessment should ideally be carried out in the context of a specific psychodermatology consultation, a brief mental health assessment could be part of the general dermatological approach to these patients. Considering that mental health, QoL and pruritus are closely linked, psychotherapeutic interventions and/or psychotropic drugs should thus be considered in some patients as an adjunct to the pharmacological treatment of CP.

Polyphosphate Functions In Vivo as an Iron Chelator and Fenton Reaction Inhibitor.

Maintaining cellular iron homeostasis is critical for organismal survival. Whereas iron depletion negatively affects the many metabolic pathways that depend on the activity of iron-containing enzymes, any excess of iron can cause the rapid formation of highly toxic reactive oxygen species (ROS) through Fenton chemistry. Although several cellular iron chelators have been identified, little is known about if and how organisms can prevent the Fenton reaction. By studying the effects of cisplatin, a commonly used anticancer drug and effective antimicrobial, we discovered that cisplatin elicits severe iron stress and oxidative DNA damage in bacteria. We found that both of these effects are successfully prevented by polyphosphate (polyP), an abundant polymer consisting solely of covalently linked inorganic phosphates. Subsequent in vitro and in vivo studies revealed that polyP provides a crucial iron reservoir under nonstress conditions and effectively complexes free iron and blocks ROS formation during iron stress. These results demonstrate that polyP, a universally conserved biomolecule, plays a hitherto unrecognized role as an iron chelator and an inhibitor of the Fenton reaction.IMPORTANCE How do organisms deal with free iron? On the one hand, iron is an essential metal that plays crucial structural and functional roles in many organisms. On the other hand, free iron is extremely toxic, particularly under aerobic conditions, where iron rapidly undergoes the Fenton reaction and produces highly reactive hydroxyl radicals. Our study now demonstrates that we have discovered one of the first physiologically relevant nonproteinaceous iron chelators and Fenton inhibitors. We found that polyphosphate, a highly conserved and ubiquitous inorganic polyanion, chelates iron and, through its multivalency, prevents the interaction of iron with peroxide and therefore the formation of hydroxyl radicals. We show that polyP provides a crucial iron reservoir for metalloproteins under nonstress conditions and effectively chelates free iron during iron stress. Importantly, polyP is present in all cells and organisms and hence is likely to take on this crucial function in both prokaryotic and eukaryotic cells.

Depression, Loneliness, and Suicide Risk among Latino College Students: A Test of a Psychosocial Interaction Model.

This study tested a psychosocial model of suicide risk in a sample of 156 Latino college students. Specifically, depression and loneliness were hypothesized to be important predictors of suicide risk (namely, hopelessness and suicidal behaviors) in Latino students. Results of conducting regression analyses indicated that, independent of age and gender, depression and loneliness were significant predictors of both indices of suicide risk examined in the present study. It is noteworthy that within the psychosocial predictor set of depression and loneliness, depression was consistently found to be nearly twice as strong a predictor than was loneliness. Moreover, we found evidence for a significant depression-loneliness interaction effect in predicting suicide risk. That is, the highest level of suicide risk was found among dysphoric Latino students who were also socially isolated. Our findings indicate that depression and loneliness are important factors to consider in understanding suicide risk among Latino college students.