Crystal structure of the phosphorylated Arabidopsis MKK5 reveals activation mechanism of MAPK kinases.

The mitogen-activated protein kinase (MAPK) signaling pathways are highly conserved in eukaryotes, regulating various cellular processes. The MAPK kinases (MKKs) are dual specificity kinases, serving as convergence and divergence points of the tripartite MAPK cascades. Here, we investigate the biochemical characteristics and three-dimensional structure of MKK5 in Arabidopsis (AtMKK5). The recombinant full-length AtMKK5 is phosphorylated and can activate its physiological substrate AtMPK6. There is a conserved kinase interacting motif (KIM) at the N-terminus of AtMKK5, indispensable for specific recognition of AtMPK6. The kinase domain of AtMKK5 adopts active conformation, of which the extended activation segment is stabilized by the phosphorylated Ser221 and Thr215 residues. In line with sequence divergence from other MKKs, the αD and αK helices are missing in AtMKK5, suggesting that the AtMKK5 may adopt distinct modes of upstream kinase/substrate binding. Our data shed lights on the molecular mechanisms of MKK activation and substrate recognition, which may help design specific inhibitors targeting human and plant MKKs.

The impact of nurses' sense of security on turnover intention during the normalization of COVID-19 epidemic: The mediating role of work engagement.

Background: COVID-19 pandemic has entered a normal stage in China. During this phase, nurses have an increased workload and mental health issues that threaten the sense of security. Poor sense of security may have a considerable impact on turnover intention through low work engagement. It was challenging to maintain the nurse workforce. Fewer studies have been conducted on the effect of nurses' sense of security on their turnover intention in that phase. This study aimed to investigate the interrelationship between nurses' sense of security, work engagement, and turnover intention during the normalization phase of the epidemic in China and to explore the impact of sense of security on turnover intention. Methods: A cross-sectional survey was conducted from September 2020 to May 2021 in Guangdong Province, China. Data were collected online using Sense of Security Scale for Medical Staff (SSS-MS), Utrecht Work Engagement Scale (UWES), and Turnover Intention Scale. Pearson's correlation analysis was used to assess the correlation between sense of security, work engagement, and turnover intention. The hypothesis model used multiple linear regression models and the bootstrapping procedure to analyze the relationship between these variables. Results: Data were collected from 2,480 nurses who met the inclusion criteria. Over half(64.5%) of nurses had a high and very high turnover intention. After controlling the demographic and working variables, sense of security (ß = 0.291, P < 0.001) had a direct positive effect on work engagement. Sense of security (ß = -0.447, P < 0.001) and work engagement (ß = -0.484, P < 0.001) had a direct negative effect on turnover intention. Sense of security and all of its components were associated with turnover intention through the partially mediating effects of work engagement. Conclusions: Nurses' turnover intention was at a high level during the normalization phase of the epidemic. Sense of security and its components act as positive resources to reduce turnover intention by improving work engagement. Policy makers and managers may pay attention to the needs of nurses' sense of security, which may be a new perspective to help managers reduce their turnover intention and stabilize the nurse team.

The impact of obesity epidemic on type 2 diabetes in children and adolescents: A systematic review and meta-analysis.

AIM: To assess the impact of the obesity epidemic on type 2 diabetes (T2D), prediabetes and glycometabolic indices in children and adolescents. METHODS: We searched four electronic databases (PubMed, Embase, Cochrane and Web of Science). Cross-sectional or cohort studies that reported on obesity and the prevalence of T2D or prediabetes in children and adolescents were reviewed. The study design, sample size and clinical outcomes were extracted from each study. The prevalence of T2D and prediabetes from the studies were pooled using meta-analysis methods. RESULTS: Meta-analysis of 228184 participants showed that the prevalence of T2D was 1.3% (95% confidence interval (CI), 0.6-2.1%) in obese subjects, which was 13 times that in normal weight subjects (0.1%, 95% CI, 0.01-0.2%). The prevalence of prediabetes in obese subjects was 3 times that in normal subjects at 17.0% (13.0-22.0%) vs. 6.0% (0.01-11.0%). Moreover, BMI was positively correlated with the prevalence of T2D, prediabetes and glycometabolic indices in obese children and adolescents. CONCLUSION: The pooled results confirm that obesity in children and adolescents leads to statistically significant increases in the prevalence of T2D and prediabetes and in glycometabolic indicator levels.