A novel CDC25A/DYRK2 regulatory switch modulates cell cycle and survival.

The cell division cycle 25A (CDC25A) phosphatase is a key regulator of cell cycle progression that acts on the phosphorylation status of Cyclin-Cyclin-dependent kinase complexes, with an emergent role in the DNA damage response and cell survival control. The regulation of CDC25A activity and its protein level is essential to control the cell cycle and maintain genomic integrity. Here we describe a novel ubiquitin/proteasome-mediated pathway negatively regulating CDC25A stability, dependent on its phosphorylation by the serine/threonine kinase DYRK2. DYRK2 phosphorylates CDC25A on at least 7 residues, resulting in its degradation independent of the known CDC25A E3 ubiquitin ligases. CDC25A in turn is able to control the phosphorylation of DYRK2 at several residues outside from its activation loop, thus affecting DYRK2 localization and activity. An inverse correlation between DYRK2 and CDC25A protein amounts was observed during cell cycle progression and in response to DNA damage, with CDC25A accumulation responding to the manipulation of DYRK2 levels or activity in either physiological scenario. Functional data show that the pro-survival activity of CDC25A and the pro-apoptotic activity of DYRK2 could be partly explained by the mutual regulation between both proteins. Moreover, DYRK2 modulation of CDC25A expression and/or activity contributes to the DYRK2 role in cell cycle regulation. Altogether, we provide evidence suggesting that DYRK2 and CDC25A mutually control their activity and stability by a feedback regulatory loop, with a relevant effect on the genotoxic stress pathway, apoptosis, and cell cycle regulation.

Functional and proteomic analysis of a full thickness filaggrin-deficient skin organoid model.

Background: Atopic eczema is an itchy inflammatory disorder characterised by skin barrier dysfunction. Loss-of-function mutations in the gene encoding filaggrin ( FLG) are a major risk factor, but the mechanisms by which filaggrin haploinsufficiency leads to atopic inflammation remain incompletely understood. Skin as an organ that can be modelled using primary cells in vitro provides the opportunity for selected genetic effects to be investigated in detail. Methods: Primary human keratinocytes and donor-matched primary fibroblasts from healthy individuals were used to create skin organoid models with and without siRNA-mediated knockdown of FLG. Biological replicate sets of organoids were assessed using histological, functional and biochemical measurements. Results: FLG knockdown leads to subtle changes in histology and ultrastructure including a reduction in thickness of the stratum corneum and smaller, less numerous keratohyalin granules. Immature organoids showed some limited evidence of barrier impairment with FLG knockdown, but the mature organoids showed no difference in transepidermal water loss, water content or dye penetration. There was no difference in epidermal ceramide content. Mass spectrometry proteomic analysis detected >8000 proteins per sample. Gene ontology and pathway analyses identified an increase in transcriptional and translational activity but a reduction in proteins contributing to terminal differentiation, including caspase 14, dermokine, AKT1 and TGF-beta-1. Aspects of innate and adaptive immunity were represented in both the up-regulated and down-regulated protein groups, as was the term 'axon guidance'.      Conclusions: This work provides further evidence for keratinocyte-specific mechanisms contributing to immune and neurological, as well as structural, aspects of skin barrier dysfunction. Individuals with filaggrin deficiency may derive benefit from future therapies targeting keratinocyte-immune crosstalk and neurogenic pruritus.

Effect of a sand or firm-surface walking program on health, strength, and fitness in women 60-75 years old.

The effects of 8 wk of soft-sand (n = 19) and firm-surface walking (n = 19) on blood lipids, submaximal fitness (8-min walk at 4.5 km/hr), and leg strength in elderly (60+ yr), sedentary women were studied. Significant main time effects (p < .005) were found for blood lipids. The surface interaction effect for high-density lipoprotein approached significance (p = .052), with a tendency for higher levels in the sand group postintervention (p = .06). Neither group reported significant differences across time for submaximal oxygen consumption (p = .223), but a greater percentage reduction in heart-rate response to the 8-min walk was reported in the sand group (p = .016). Knee strength did not change in either group, whereas hip strength significantly improved in both groups (p = .0001), with larger effect sizes reported in the sand group. Overall, both groups showed improvements in blood lipids, fitness, and strength, with strength changes being slightly higher in the sand-walking group.

Differentiating between physically violent and nonviolent stalkers: an examination of Canadian cases.

This study is one of a few that empirically investigated factors that differentiated the physically violent stalker from the nonviolent stalker. Using discriminant analysis, 103 Canadian cases of "simple obsessional" stalking were examined. Overall, the success of the model for classifying cases into one of two groups was 81%. Results revealed that the physically violent stalker is more likely to: (a) have a stronger previous emotional attachment toward their victim; (b) be more highly fixated/obsessed with their victim; (c) have a higher degree of perceived negative affect towards their victim; (d) engage in more verbal threats toward the victim; and (e) have a history of battering/domestic abuse towards the victim. Overall, the variables that best differentiate the physically violent stalker from the nonviolent one appear to characterize underlying themes of anger, vengeance, emotional arousal, humiliation, projection of blame, and insecure attachment pathology.

A case of stalking in the workplace and subsequent sexual homicide.

A case of stalking in the workplace and subsequent sexual homicide by a 33-year-old male is reported. Following several months of stalking a 38-year-old female, the male subject went to the woman's office after business hours and restrained, raped, and murdered her. The cause of death was multiple stab wounds. The facts of the case reveal that the subject fits a predatory-type stalker, which represents a small subgroup within stalkers that has received little attention. Unlike other types of stalkers, the predatory stalker gives little warning to their victim (or multiple victims), as their stalking behaviors tend not to be very invasive or harassing. In general, most stalkers are not physically violent; however, predatory-type stalkers, given their tendency for sexual violence, are dangerous and the importance of identifying them is emphasized. Factors associated with perpetrators of sexual homicide are discussed.